Anatomi & Fisiologi-nota ringkas

Anatomy and Physiology Notes

Introduction to A&P Introduction to Basic Chemistry The Generalized Animal Cell Tissues The Skin The Skeletal System The Muscular System The Nervous System

The Endocrine System and Glands The Cardiovascular System Lymphatic System The Respiratory System Digestive System Urinary System Reproductive System

Anatomy and Physiology Defined:

1. Anatomy is the study of structure and the relationship among structures.
   • Types of anatomy include:
     • Surface Anatomy (form and markings of surface features)
     • Gross Anatomy (macroscopic)
     • Systemic or Systematic anatomy (systems)
     • Regional Anatomy (regions)
     • Developmental Anatomy (development from fertilization to adulthood)
     • Embryology (development from fertilized egg through eighth week in utero)
     • Pathological Anatomy (disease)
     • Histology (tissues)
     • Cytology (cells)
     • Radiographic Anatomy (x-rays).
2. Physiology is the study of how body structures function. It is based upon the concepts
   of biochemistry.

Levels of Structural Organization:

1. The human body consists of several levels of structural organization; among these are
   the chemical, cellular, tissue, organ, system, and organismic levels.
2. Cells are the basic structural and functional units of an organism.
3. Tissues consist of groups of similarly specialized cells and their intercellular
   material that perform certain special functions.
4. Organs are structures of definite form and function composed
   of two or more different tissues.
5. Systems consist of associations of organs that have a common function.
6. The human organism is a collection of structurally and functionally integrated systems.
7. The systems of the human body are the integumentary, skeletal, muscular, nervous,
   endocrine, cardiovascular, Iymphatic, respiratory, digestive, urinary, and reproductive.
   

Structural Plan:

1. The human body has certain general characteristics.
2. Among the characteristics are a backbone, a tube within a tube organization, and
   bilateral symmetry.

Anatomical Position:

When in the anatomical position, the subject stands erect facing the observer, the upper extremities are placed at the sides, and the palms of the hands are turned forward.

Anatomical Names:

Regional names are terms given to specific regions of the body for reference. Examples of regional names include cranial (skull), thoracic (chest), brachial (arm), patellar (knee), cephalic (head), and gluteal (buttock).

Directional Terms:

1. Directional terms indicate the relationship of one part of the body to another.
2. Commonly used directional terms are:
   • superior (toward the head or upper part of a structure)
   • inferior (away from the head or toward the lower part of a structure)
   • anterior (near or at the front of the body)
   • posterior (near or at the back of the body)
   • medial (nearer the midline of the body or a structure)
   • lateral (near or towards the side of the body or a structure)
   • intermediate (between a medial and lateral structure)
   • ipsilateral (on the same side of the body)
   • contralateral (on the opposite side of the body)
   • proximal (nearer the attachment of an extremity to the trunk or a structure)
   • distal (farther from the attachment of an extremity to the trunk or a structure)
   • superficial (toward or on the surface of the body)
   • deep (away from the surface of the body)
   • parietal (pertaining to the outer wall of a body cavity)
   • visceral (pertaining to the covering of an organ).

Planes and Sections:

Planes are imaginary flat surfaces that are used to divide the body or organs into definite areas. A midsagittal (median) plane is a vertical plane through the midline of the body that divides the body or organs into equal right and left sides, a sagittal (parasagittal) plane is a plane parallel to the midsagittal plane that divides the body or organs into unequal right and left sides; a frontal (coronal) plane is a plane at a right angle to a midsagittal (or sagittal) plane that divides the body or organs into anterior and posterior portions; and a horizontal (transverse) plane is a plane parallel to the ground and at a right angle to the midsagittal, sagittal, and frontal planes that divides the body or organs into superior and inferior portions.

Sections are flat surfaces resulting from cuts through body structures. They are named according to the plane on which the cut is made and include cross sections, frontal sections, and midsagittal sections.

Body Cavities:

1. Spaces in the body that contain internal organs are called cavities.
2. The dorsal and ventral cavities are the two principal body cavities. The dorsal cavity contains the brain and spinal cord. The organs of the ventral cavity are collectively called the viscera.
3. The dorsal cavity is subdivided into the cranial cavity, which contains the brain, and the vertebral or spinal canal, which contains the spinal cord and beginnings of spinal nerves.
4. The ventral body cavity is subdivided by the diaphragm into an upper thoracic cavity and a lower abdominopelvic cavity.
5. The thoracic cavity contains two pleural cavities and a mediastinum, which includes the pericardial cavity.
6. The mediastinum is a mass of tissue between the pleurae of the lungs that extends from the sternum to the vertebral column; it contains all contents of the thoracic cavity, except the lungs.
7. The abdominopelvic cavity is divided into a superior abdominal and an inferior pelvic cavity by an imaginary line extending from the symphysis pubis to the sacral promontory.
8. Viscera of the abdominal cavity include the stomach, spleen, pancreas, liver, gallbladder, kidneys, small intestine, and most of the large intestine.
9. Viscera of the pelvic cavity include the urinary bladder, sigmoid colon, rectum, and internal female and male reproductive structures.

Abdominopelvic Regions:

1. To describe the location of organs easily, the abdominopelvic cavity may be divided into nine regions by drawing four imaginary lines.
2. The names of the nine abdominopelvic regions are epigastric, right hypochondriac, left hypochondriac, umbilical, right lumbar, left lumbar, hypogastric (pubic), right iliac (inguinal), and left iliac (inguinal).

Abdominopelvic Quadrants:

1. To locate the site of an abdominopelvic abnormality in clinical studies, the abdominopelvic cavity may be divided into four quadrants by passing imaginary horizontal and vertical lines through the umbilicus.
2. The names of the four abdominopelvic quadrants are right upper quadrant (RUQ), left upper quadrant (LUQ), right lower quadrant (RLQ). And left lower quadrant (LLQ).

Homeostasis:

1. Homeostasis is a condition in which the internal environment (extracellular fluid) of the body remains relatively constant in terms of chemical composition, temperature, and pressure.
2. All body systems attempt to maintain homeostasis.
3. Homeostasis is controlled mainly by the nervous and endocrine systems.

Stress and Homeostasis:

1. Stress is any external or internal stimulus that creates a change in the internal environment.
2. If a stress acts on the body, homeostatic mechanisms attempt to counteract the effects of the stress and bring the condition back to normal.

Homeostasis of Blood Pressure:

1. Blood pressure (BP) is the force exerted by blood as it presses against and attempts to stretch the walls of arteries. It is determined by the rate and force of the heartbeat, the amount of blood, and arterial resistance.
   
2. If a stress causes the heartbeat to increase. blood pressure also increases; pressure-sensitive nerve cells in certain arteries inform the brain, and the brain responds by sending impulses that decrease heartbeat, thus decreasing blood pressure back to normal; a rise in blood pressure also causes the brain to send impulses that dilate arterioles, thereby also helping to decrease blood pressure back to normal.
   
3. Any circular situation in which information about the status of something is continually fed back to a control region is called a feedback system.
   
4. A negative feedback system is one in which the reaction of the body (output) counteracts the stress (input) in order to maintain homeostasis; most feedback systems of the body are negative. A positive feedback system is one in which the output intensifies the input; the system is usually destructive.

Homeostasis of Blood Sugar Level:

1. A normal blood sugar (BS) level is maintained by the actions of two different pancreatic hormones: insulin and glucagon.
2. Insulin lowers blood sugar level by increasing sugar uptake by cells and accelerating sugar storage as glycogen in the liver and skeletal muscles.
3. Glucagon raises blood sugar level by accelerating the rate of sugar released from glycogen by the liver.
   

Measuring the Human Body:

1. Various kinds of measurements are important in understanding the human body.
2. Examples of such measurements include organ dimensions and weight, physiological response time, and amount of medication to be administered.
3. Measurements utilized in scientific procedures are given in metric units.
   

Introduction to Basic Chemistry:

Chemical Elements:

• Matter is anything that occupies space and has mass. It is made up of building units called chemical elements.
• Carbon, hydrogen, oxygen, and nitrogen make up 96 percent of body weight. These elements together with phosphorus and calcium make up 99 percent of total body weight.

Structure of Atoms:

1. Units of matter of all chemical elements are called atoms.
2. Atoms consist of a nucleus, which contains protons and neutrons, and orbiting electrons moving in energy levels.
3. The total number of protons of an atom is its atomic number. This number is equal to the number of electrons in the atom.

Atoms and Molecules:

1. The electrons are the part of an atom that actively participate in chemical reactions.
2. A molecule is the smallest unit of two or more combined atoms. A molecule containing two or more different kinds of atoms is a compound.

Chemical Bonds:

• In an ionic bond, outer energy level electrons are transferred from one atom to another. The transfer forms ions, whose unlike charges attract each other and form ionic bonds.
• In a covalent bond, there is a sharing of pairs of outer-energy level electrons.
• Hydrogen bonding provides temporary bonding between certain atoms within large complex molecules such as proteins and nucleic acids.
  

Chemical Reactions:

1. Synthesis reactions involve the combination of reactants to produce a new molecule. The reactions are anabolic: bonds are formed.
2. In decomposition reactions, a substance breaks down into other substances. The reactions are catabolic: bonds are broken.
3. Exchange reactions involve the replacement of one atom or atoms by another atom or atoms.
4. In reversible reactions, end products can revert to the original combining molecules.
5. The sum of all synthetic and decomposition reactions that occur within an organism is referred to as metabolism.
6. When chemical bonds are formed, energy is needed. When bonds are broken, energy is released. This is known as chemical bond energy.
   

Chemical Compounds and Life Processes:

1. 1. Inorganic substances usually lack carbon, contain ionic bonds, resist decomposition, and dissolve readily in water.
2. 2. Organic substances always contain carbon and usually hydrogen. Most organic substances contain covalent bonds and many are insoluble in water.

Inorganic Compounds:

1. Water is the most abundant substance in the body. It is an excellent solvent and suspending medium, participates in chemical reactions, absorbs and releases heat slowly, and lubricates.
2. Acids, bases, and salts dissociate into ions in water. An acid ionizes into H+ ions, a base ionizes into OH- ions. A salt ionizes into neither H+ nor OH- ions. Cations are positively charged ions; anions are negatively charged ions.
3. The pH of different parts of the body must remain fairly constant for the body to remain healthy. On the pH scale, 7 represents neutrality. Values below 7 indicate acid solutions, and values above 7 indicate alkaline solutions.
4. The pH values of different parts of the body are maintained by buffer systems, which usually consist of a weak acid and a weak base. Buffer systems eliminate excess H+ ions and excess OH- ions in order to maintain pH homeostasis.

Organic Compounds:

1. Carbohydrates are sugars or starches that provide most of the energy needed for life. They may be monosaccharides, disaccharides, or polysaccharides. Carbohydrates, and other organic molecules, are joined together to form larger molecules with the loss of water by a process called dehydration synthesis. In the reverse process called digestion or hydrolysis, large molecules are broken down into smaller ones by the addition of water.
2. Lipids are a diverse group of compounds that includes the fats, phospholipids, steroids, vitamins E and K, and prostaglandins. Fats protect, insulate, provide energy, and are stored. Prostaglandins mimic the effects of hormones and are involved in the inflamitory response and the modulation of hormonal responses.
3. Proteins are constructed from amino acids. They give structure to the body, regulate processes, provide protection, help muscles to contract, transport substances, and serve as enzymes.
4. Deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) are nucleic acids consisting of nitrogen bases, sugar, and phosphate groups. DNA is a double helix and is the primary chemical in genes. RNA differs in structure and chemical composition from DNA and is mainly concerned with protein synthesis reactions.
5. Adenosine triphosphate (ATP) is the major energy storing molecule of living things. When its energy is liberated, it is decomposed to adenosine diphosphate (ADP). ATP is manufactured from ADP using the energy supplied by various decomposition reactions, particularly of glucose.
6. Cyclic AMP (second messenger) is closely related to ATP and assumes a function in certain hormonal reactions within the cell.

CELLS

The Generalized Animal Cell:

1. A cell is the basic, living, structural and functional unit of the body.
2. A generalized cell is a composite that represents various cells of the body.
3. Cytology is the science concerned with the study of cells.
4. The principal parts of a cell are the plasma (cell) membrane, cytoplasm, organelles, and inclusions. Extracellular materials are manufactured by the cell and deposited outside the plasma membrane.
   

Plasma (Cell) Membrane:

1. The plasma (cell) membrane, surrounds the cell and separates it from other cells and the external environment.
2. It is composed primarily of proteins and phospholipids. According to the fluid mosaic model, the membrane consists of a phospholipid bilayer with integral and peripheral proteins.

   Functions:
   

   1. Functionally, the plasma membrane facilitates contact with other cells, provides receptors, and mediates the passage of materials.
   2. The membrane's selectively permeable nature restricts the passage of certain substances. Substances can pass through the membrane depending on their molecular size, lipid solubility, electrical charges, and the presence of carriers.

Movement of Materials Across Plasma Membranes:

1. Passive processes involve the kinetic energy of individual molecules.
2. Diffusion is the net movement of molecules or ions from an area of higher concentration to an area of lower concentration until an equilibrium is reached.
3. In facilitated diffusion, certain molecules, such as glucose, combine with a carrier to become soluble in the phospholipid portion of the membrane.
4. Osmosis is the movement of water through a selectively permeable membrane from an area of higher water concentration to an area of lower water concentration.
5. In an isotonic solution, red blood cells maintain their normal shape; in a hypotonic solution, they undergo hemolysis; in a hypertonic solution, they undergo crenation.
6. Filtration is the movement of water and dissolved substances across a selectively permeable membrane by pressure.
7. Dialysis is the diffusion of solute particles across a selectively permeable membrane and involves the separation of small molecules from large molecules.
8. Active processes involve the use of ATP by the cell.
9. Active transport is the movement of ions across a cell membrane from lower to higher concentration.
10. Endocytosis in the movement of substances through plasma membranes in which the membrane surrounds the substance, encloses it, and brings it into the cell.
11. Phagocytosis is the ingestion of solid particles by pseudopodia. It is an important process used by white blood cells to destroy bacteria that enter the body.
12. Pinocytosis is the ingestion of a liquid by the plasma membrane. In this process, the liquid becomes surrounded by a vacuole.
13. Receptor-mediated endocytosis in the selective uptake of large molecules and particles by cells.

Cytoplasm:

1. Cytoplasm is the substance inside the cell that contains organelles and inclusions.
2. It is composed mostly of water plus proteins, carbohydrates, lipids, and inorganic substances. The chemicals in cytoplasm are either in solution or in a colloid (suspended) form.
3. Functionally, cytoplasm is the medium in which chemical reactions occur.

Organelles:

1. Organelles are specialized portions of the cell that carry on specific activities.
2. They assume specific roles in cellular growth, maintenance, repair, and control.

Nucleus:

1. Usually the largest organelle, the nucleus controls cellular activities and contains the genetic information.
2. Cells without nuclei, such as mature red blood cells, do not grow or reproduce.
3. The parts of the nucleus include the nuclear membrane, karyolymph, nucleoli, and genetic material (DNA), comprising the chromosomes.
4. Chromosomes consist of DNA and histones and consist of subunits called nucleosomes.

Ribosomes:

1. Ribosomes are granular structures consisting of ribosomal RNA and ribosomal proteins.
2. They occur free (singly or in clusters) or in conjunction with endoplasmic reticulum.
3. Functionally, ribosomes are the sites of protein synthesis.

Endoplasmic Reticulum:

1. The ER is a network of parallel membranes continuous with the plasma membrane and nuclear membrane.
2. Granular or rough ER has ribosomes attached to it. Agranular or smooth ER does not contain ribosomes.
3. The ER provides mechanical support, conducts intracellular nerve impulses in muscle cells, exchanges materials with cytoplasm, transports substances intracellularly, stores synthesized molecules. and helps export chemicals from the cell.
   

Golgi Complex (Golgi Body):

1. The Golgi complex consists of four to eight stacked, membranous sacs called cisternae.
2. In conjunction with the ER, the Golgi complex secretes proteins and lipids and synthesizes and secretes glycoproteins.
3. It is particularly prominent in secretory cells such as those in the pancreas or salivary glands.

Mitochondria:

1. Mitochondria consist of a smooth outer membrane and a folded inner membrane surrounding the interior matrix. The inner folds are called cristae.
2. The mitochondria are called "powerhouses of the cell" because ATP is produced in them.
3. Today mitochondria are generally considered to be endosymbionts rather than simply cellular organelles.

Lysosomes:

1. Lysosomes are spherical structures that contain digestive enzymes. They are formed from Golgi complexes.
2. They are found in large numbers in white blood cells, which carry on phagocytosis.
3. If the cell is injured, Iysosomes release enzymes and digest the cell. Thus they are called "suicide packets."
4. Lysosomes are also involved in bone removal and remodeling.

Peroxisomes:

1. Peroxisomes are similar in structure to Iysosomes, but smaller.
2. They contain enzymes (e.g., catalase) involved in the metabolism of hydrogen peroxide.

Microfilaments and Microtubules - The Cytoskeleton:

1. Together microfilaments and microtubules form the cytoskeleton.
2. Microfilaments are rodlike structures consisting of the protein actin or myosin. They are involved in muscular contraction, support, and movement.
3. Microtubules are cylindrical structures consisting of the protein tubulin. They support, provide movement, and form the structure of flagella, cilia, centrioles, and the mitotic spindle.

Centrosome and Centrioles:

1. The dense area of cytoplasm containing the centrioles is called a centrosome. It is located near the nucleus.
2. Centrioles are paired cylinders arranged at right angles to one another. They assume an important role in cell reproduction.

Flagella and Cilia:

1. These cellular projections have the same basic structure and are used in movement.
2. If projections are few and long, they are called flagella. If they are numerous and hairlike, they are called cilia.
3. The flagellum on a sperm cell moves the entire cell. The cilia on cells of the respiratory tract move foreign matter trapped in mucus along the cell surfaces toward the throat for elimination.

Cellular Inclusions:

1. Cell inclusions are chemical substances produced by cells. They are usually organic and may have recognizable shapes
2. Examples are melanin, glycogen, lipids, and mucus.

Extracellular Materials:

1. These are all the substances that lie outside the cell membrane.
2. They provide support and a medium for the diffusion of nutrients and wastes.
3. Some, like hyaluronic acid and chondroitin sulfate, are amorphous. Others, like collagenous, reticular, and elastic fibers, are fibrous.

Cell Division:

1. Cell division is the process by which cells reproduce themselves. It consists of nuclear division and cytoplasmic division (cytokinesis).
2. Cell division that results in the production of sperm and eggs is called reproductive cell division and consists of a nuclear division called meiosis and cytokinesis.
3. Cell division that results in an increase in body cells is called somatic cell division and involves a nuclear division called mitosis and cytokinesis.

Somatic Cell Division:

1. Prior to mitosis and cytokinesis, the DNA molecules, or chromosomes, replicate themselves so the same chromosomal complement can be passed on to future generations of cells.
2. A cell carrying on such every life process except division is said to be in interphase or metabolic interphase.
3. Mitosis is the distribution of two sets of chromosomes into separate and equal nuclei following their replication.
4. It consists of prophase, metaphase, anaphase, and telophase.
5. Cytokinesis begins in late anaphase and terminates in telophase.
6. A cleavage furrow forms at the cell's equator and progresses inward, cutting through the cell to form two separate portions of cytoplasm.

Gene Action - Protein Synthesis:

1. Most of the cellular machinery is concerned with synthesizing proteins.
2. Cells make proteins by translating the genetic information encoded in DNA into specific proteins. This involves transcription and translation.
3. In transcription, genetic information encoded in DNA is copied by a strand of messenger RNA (mRNA); the DNA strand that serves as the template is called the sense strand.
4. DNA also synthesizes ribosomal RNA (rRNA) and template or transfer RNA (tRNA).
5. The process of using the information in the nitrogen base sequence of mRNA to dictate the amino acid sequence of a protein is known as translation.
6. mRNA associates with ribosomes, which consist of rRNA and protein.
7. Specific amino acids are attached to molecules of tRNA. Another portion of the tRNA has a triplet of bases called an anticodon; a codon is a segment of three bases of mRNA.
8. tRNA delivers a specific amino acid to the codon; the ribosome moves along an mRNA strand as amino acids are joined to form a growing polypeptide.

"SOS" Genes - DNA Repair:

1. The structure of DNA is vulnerable to damage by harmful radiations and various chemicals.
2. Damage could lead to cellular malfunction that might lead to cancer.
3. In response to DNA damage, an "SOS response" occurs; certain genes produce enzymes that repair genetic damage. DNA Polymerase is an example.

Cells and Aging:

1. Aging is a progressive failure of the body's homeostatic adaptive responses.
2. Many theories of aging have been proposed, including genetically programmed cessation of cell division and excessive immune responses, but none successfully answers all questions.
3. All of the various body systems exhibit definitive and sometimes extensive changes with aging

Disorders: Homeostatic Imbalances

1. Cancerous tumors are referred to as malignant; noncancerous tumors are called benign; the study of tumors is called oncology.
2. The spread of cancer from its primary site is called metastasis.
3. Carcinogens include environmental agents and viruses.

Tissues

Types of Tissues

1. A tissue is a group of similar cells and their intercellular substance specialized for a particular function.
2. Depending on their function and structure, the various tissues of the body are classified into four principal types: epithelial, connective. muscular. and nervous.

Epithelial Tissue:

1. Epithelium has many cells, little intracellular material, and no blood vessels (avascular). It is attached to connective tissue by a basement membrane. It can replace itself.
2. The subtypes of epithelium include covering and lining epithelium and glandular epithelium.

Covering and Lining Epithelium:

1. Layers are arranged as simple (one layer), stratified (several layers), and pseudostratified (one layer that appears as several); cell shapes include squamous (flat), cuboidal (cubelike), columnar (rectangular), and transitional (variable).
2. Simple squamous epithelium is adapted for diffusion and filtration and is found in lungs and kidneys. Endothelium lines the heart and blood vessels. Mesothelium lines the thoracic and abdominopelvic cavities and covers the organs within them.
3. Simple cuboidal epithelium is adapted for secretion and absorption. It is found covering ovaries, in kidneys and eyes, and lining some glandular ducts.
4. Nonciliated simple columnar epithelium lines most of the digestive tract. Specialized cells containing microvilli perform absorption. Goblet cells perform secretion of mucus. In a few portions of the respiratory tract, the cells are ciliated to move foreign particles trapped in mucus out of the body.
5. Stratified squamous epithelium is protective. It lines the upper digestive tract and vagina and forms the outer layer of skin.
6. Stratified cuboidal epithelium is found in adult sweat glands, portion of urethra, pharynx, and epiglottis.
7. Stratified columnar epithelium protects and secretes. It is found in the male urethra and large excretory ducts.
8. Transitional epithelium lines the urinary bladder and is capable of stretching.
9. Pseudostratified epithelium has only one layer but gives the appearance of many. It lines larger excretory ducts, parts of urethra, auditory tubes, and most upper respiratory structures, where it protects and secretes.

Glandular Epithelium:

1. A gland is a single cell or a mass of epithelial cells adapted for secretion.
2. Exocrine glands (sweat, oil, and digestive glands) secrete into ducts or directly onto a free surface.
3. Structural classification includes unicellular and multicellular glands. Multicellular glands are further classified as tubular, acinar, tubuloacinar, simple, and compound.
4. Functional classification includes holocrine, merocrine, and apocrine glands.
5. Endocrine glands secrete hormones directly into the blood.

Connective Tissue:

1. Connective tissue is the most abundant body tissue. It has few cells, an extensive intercellular substance, and a rich blood supply (vascular), except for cartilage. It does not occur on free surfaces.
2. The intercellular substance determines the tissue's qualities.
3. Connective tissue protects, supports, and binds organs together.
4. Connective tissue is classified into two principal types: embryonic and adult.

Embryonic Connective Tissue:

1. Mesenchyme forms all other connective tissues.
2. Mucous connective tissue is found in the umbilical cord of the fetus, where it gives support.

Adult Connective Tissue:

1. Adult connective tissue is connective tissue that exists in the newborn and that does not change after birth. It is subdivided into several kinds: connective tissue proper, cartilage, bone tissue, and vascular tissue.
2. Connective tissue proper has a more or less fluid intercellular material, and a typical cell is the fibroblast. Five examples of such tissues may be distinguished: Loose, Adipose, Dense, Elastic, and Reticular.
   • Loose (areolar) connective tissue is one of the most widely distributed connective tissues in the body. Its intercellular substance (hyaluronic acid) contains fibers (collagenous, elastic, and reticular) and various cells (fibroblasts, macrophages, plasma, mast, and melanocytes). Loose connective tissue is found in all mucous membranes, around body organs, and in the subcutaneous layer.
   • Adipose tissue is a form of loose connective tissue in which the cells, called adipocytes, are specialized for fat storage. It is found in the subcutaneous layer and around various organs.
   • Dense (collagenous) connective tissue has a close packing of fibers (regularly or irregularly arranged). It is found as a component of fascia, membranes of organs, tendons, ligaments, and aponeuroses.
   • Elastic connective tissue has a predominance of freely branching elastic fibers that give it a yellow color. It is found in the cartilages of the larynx, elastic arteries, trachea, bronchial tubes. and true vocal cords.
   • Reticular connective tissue consists of interlacing reticular fibers and forms the stroma of the liver, spleen, and Iymph nodes.
3. Cartilage has a jellylike matrix containing collagenous and elastic fibers and chondrocytes.
4. The growth of cartilage is accomplished by interstitial growth (from within) and appositional growth (from without).
5. Hyaline cartilage is found in the embryonic skeleton, at the ends of bones, in the nose, and in respiratory structures. It is flexible, allows movement, and provides support.
6. Fibrocartilage connects the pelvic bones and the vertebrae. It provides strength.
7. Elastic cartilage maintains the shape of organs such as the larynx, auditory tubes, and external ear.

Muscle Tissue and Nervous Tissue:

1. Muscle tissue performs one major function - contraction. There are three types of muscle tissue: Skeletal (striated), Visceral (smooth), and Cardiac.
2. Nervous tissue is specialized to conduct electrical impulses.

Membranes:

1. An epithelial membrane is an epithelial layer overlying a connective tissue layer. Examples are: mucous, serous, and cutaneous.
   • Mucous membranes line cavities that open to the exterior, such as the digestive tract.
   • Serous membranes (pleura, pericardium, peritoneum) line closed cavities and cover the organs in the cavities. These membranes consist of parietal and visceral portions.
   • The cutaneous membrane is the skin.
2. Synovial membranes line joint cavities and do not contain epithelium.

Tissue Inflammation - An Attempt to Restore Homeostasis:

1. Damage to a tissue causes an inflammatory response characterized by redness, pain, heat, and swelling; sometimes loss of function occurs.
2. The inflammatory response is initiated by histamine, serotonin, kinins, and prostaglandins released by damaged tissue. They cause vasodilation and increased permeability of blood vessels.
3. Further cell injury is prevented by phagocytes. These include neutrophils (microphages) and macrophages.
4. The role of fibrin is to isolate the infected area.
5. In most inflammations, pus is produced; if it cannot drain out of the body, an abscess develops.

Tissue Repair:

1. Tissue repair is the replacement of damaged or destroyed cells by healthy ones.
2. It begins during the active phase of inflammation and is not completed until after harmful substances in the inflamed area have been neutralized or removed.

Repair Process:

1. If the injury is superficial, tissue repair involves pus removal (if pus is present), scab formation, and parenchymal regeneration.
2. If damage is extensive, granulation tissue is involved.

Conditions for Repair:

1. Nutrition is important to tissue repair. Various vitamins (A, some B, D, C, E, and K) and a protein rich diet are needed.
2. Adequate circulation of blood is needed.
3. The tissues of young people repair rapidly and efficiently, the process slows down with aging.
   

The Integumentary System - The Skin:

Skin

1. The skin and its derivatives (hair, glands, and nails) constitute the integumentary system.
2. The skin is one of the larger organs of the body. It performs the functions of protection, maintaining body temperature, preventing excessive loss of inorganic and organic materials, receiving stimuli, storage of chemical compounds, synthesis of vitamin D, and excretion of water, salts, and several organic compounds.
3. The principal parts of the skin are the outer epidermis and inner dermis. The dermis overlies the subcutaneous layer.
4. The epidermal layers, from deepest to most superficial, are the stratum basale, spinosum, granulosum, lucidum, and corneum. The basale and spinosum undergo continuous cell division and produce all other layers.
5. The dermis consists of a papillary region and a reticular region. The papillary region is loose connective tissue containing blood vessels, nerves, hair follicles, dermal papillae, and Meissner's corpuscles. The reticular region is dense, irregularly arranged connective tissue containing adipose tissue, hair follicles, nerves, oil glands, and ducts of sweat glands.
6. Lines of cleavage indicate the direction of collagenous fiber bundles in the dermis and are considered during surgery.
7. The color of skin is due to melanin, carotene, and blood in capillaries in the dermis.
8. Epidermal ridges increase friction for better grasping ability and provide the basis for fingerprints and footprints.

Epidermal Derivatives:

Epidermal derivatives are structures developed from the embryonic epidermis.
Among the epidermal derivatives are hair, skin glands (sebaceous, sudoriferous, and ceruminous), and nails.

• Hair:
  1. Hairs are epidermal growths that function in protection.
  2. Hair consists of a shaft above the surface, a root that penetrates the dermis and subcutaneous layer, and a hair follicle.
  3. Associated with hairs are sebaceous glands, arrectores pilorum muscles, and root hair plexuses.
  4. Hair color is due to combinations of various amounts of the three hair pigments, black melanin, brown melanin, and pheomelanin (yellow). Graying is due to the loss of melanin.
  5. New hairs develop from cell division of the matrix in the bulb; hair replacement and growth occurs in a cyclic pattern. "Male-pattern" baldness is caused by androgens and heredity.
• Glands:
  1. Sebaceous (oil) glands are usually connected to hair follicles; they are absent in the palms and soles. Sebaceous glands produce sebum which moistens hairs and waterproofs the skin. Enlarged sebaceous glands may produce blackheads, pimples, and boils.
  2. Sudoriferous (sweat) glands are distinguished as apocrine and eccrine. Apocrine sweat glands are limited in distribution to the skin of the axilla, pubis, and areolae; their ducts open into hair follicles. Eccrine sweat glands have an extensive distribution; their ducts terminate at pores at the surface of the epidermis. Sudoriferous glands produce perspiration, which carries small amounts of wastes to the surface and assists in maintaining body temperature.
  3. Ceruminous glands are modified sudoriferous glands that secrete cerumen. They are found in the external auditory meatus.
• Nails:
  1. Nails are hard, keratinized epidermal cells over the dorsal surfaces of the terminal portions of the fingers and toes.
  2. The principal parts of a nail are the body, free edge, root, lunula, eponychium, hyponychium, and matrix. Cell division of the matrix cells produces new nails.

Homeostasis:

1. One of the functions of the skin is the maintenance of the normal body temperature of 37C (98.6F).
2. If environmental temperature is high, skin receptors sense the stimulus (heat) and generate impulses that are transmitted to the brain. The brain then causes the sweat glands to produce perspiration. As the perspiration evaporates, the skin is cooled.
3. The skin-cooling response is a negative feedback mechanism.
4. Temperature maintenance is also accomplished by adjusting blood flow to the skin, regulating metabolic rate, and regulating skeletal muscle contractions.

Disorders - Homeostatic Imbalances:

1. Pruritus or itching is a common skin problem that may be related to skin disorders, systemic diseases, or psychogenic factors.
2. Acne is an inflammation of sebaceous glands.
3. Impetigo is a superficial skin infection caused by bacteria and characterized by pustules that become crusted and rupture.
4. Systemic lupus erythematosus (SLE) is an autoimmune disease of connective tissue.
5. Psoriasis is a chronic skin disease characterized by reddish, raised plaques or papules.
6. Decubitus ulcers are caused by a chronic deficiency of blood to tissues subjected to prolonged pressure.
7. Warts are uncontrolled growths of epithelial skin cells caused by a virus. Most warts are benign.
8. Cold sores (fever blisters) are lesions caused by type l herpes simplex virus. The dormant infection is triggered by certain stimuli.
9. Sunburn is a skin injury resulting from prolonged exposure to the ultraviolet (UV) rays of sunlight.
10. Skin cancer can be caused by excessive exposure to sunlight.
11. Tissue damage that destroys protein is called a burn. Depending on the depth of damage, skin burns are classified as first-degree, second-degree (partial-thickness), and third-degree (full-thickness). Burn treatment may include cleansing the wound, removing dead tissue, replacing lost body fluids, and covering wounds with temporary protection, and skin grafting.

The Skeletal System:

The Skeletal System:

1. The skeletal system consists of all bones attached at joints and cartilage between joints.
2. The functions of the skeletal system include support, protection. leverage, mineral storage, and blood cell production.

Histology:

1. Osseous tissue consists of widely separated cells surrounded by large amounts of intercellular substance. The intercellular substance contains collagenous fibers and abundant hydroxyapatites (mineral salts).
2. Parts of a typical long bone are the diaphysis (shaft), epiphyses (ends), metaphysis, articular cartilage, periosteum, medullary or marrow cavity, and endosteum.
3. Compact (dense) bone consists of Haversian systems with little space between them. Compact bone lies over spongy bone and composes most of the bone tissue of the diaphyses. Functionally, compact bone protects, supports, and resists stress.
4. Spongy (cancellous) bone consists of trabeculae surrounding many red marrow-filled spaces. It forms most of the structure of short, flat, and irregular bones, and the epiphyses of long bones. Functionally, spongy bone stores marrow and provides some support.

Ossification Bone Formation:

1. Bone forms by a process called ossification or osteogenesis, which begins when mesenchymal cells become transformed into osteoblasts.
2. The process begins during the sixth or seventh week of embryonic life and continues throughout adulthood. The two types of ossification, intramembranous and endochondral, involve the replacement of a preexisting connective tissue with bone.
3. Intramembranous ossification occurs within fibrous membranes of the embryo and the adult.
4. Endochondral ossification occurs within a cartilage model. The primary ossification center of a long bone is in the diaphysis. Cartilage degenerates, leaving cavities that merge to form the marrow cavity. Osteoblasts lay down bone. Next, ossification occurs in the epiphyses, where bone replaces cartilage, except for the epiphyseal plate.
5. The anatomical zones of the epiphyseal plate are the zones of reserve cartilage, proliferating cartilage, hypertrophic cartilage, and calcified matrix.
6. Because of the activity of the epiphyseal plate, the diaphysis of a bone increases in length by appositional growth.
7. Bone grows in diameter as a result of the addition of new bone tissue by periosteal osteoblasts around the outer surface of the bone.
8. In both types of ossification, spongy bone is laid down first. Compact bone is later reconstructed from spongy bone.

Homeostasis:

1. The homeostasis of bone growth and development depends on a balance between bone formation and resorption.
2. Old bone is constantly destroyed by osteoclasts, while new bone is constructed by osteoblasts. This process is called remodeling.
3. Normal growth depends on calcium, phosphorus, and vitamins (A, C, and D) and is controlled by hormones that are responsible for bone mineralization and resorption.

Disorders - Homeostatic Imbalances:

1. Rickets is a vitamin D deficiency in children in which the body does not absorb calcium and phosphorus. The bones soften and bend under the body's weight.
2. Osteomalacia is a vitamin D deficiency in adults that leads to demineralization.
3. Osteoporosis is a decrease in the amount and strength of bone tissue due to decreases in hormone output.
4. Paget's disease is the irregular thickening and softening of bones, apparently related to an imbalance between osteoclast and osteoblast activities.
5. Osteomyelitis is a term for the infectious diseases of bones, marrow, and periosteum. It is frequently caused by staphylococcus bacteria.
6. A fracture is any break in a bone.
7. The types of fractures include: partial, complete, simple, compound, comminuted, greenstick, spiral, transverse, impacted, Pott's, Colles', displaced, and nondisplaced.
8. Fracture repair consists of forming a fracture hematoma, forming a callus, and remodeling.
9. Treatment by pulsating electromagnetic fields (PEMFs) has provided dramatic results in healing fractures that would otherwise not have mended properly. Its application for limb regeneration and stopping the growth of tumor cells is being investigated.

Types of Bones:

1. On the basis of shape, bones are classified as long, short, flat, or irregular.
2. Wormian or sutural bones are found between the sutures of certain cranial bones. Sesamoid bones develop in tendons or ligaments. The patella is an example.

Surface Markings:

1. Markings are areas on the surfaces of bones.
2. Each marking is structured for a specific function-joint formation, muscle attachment, or passage of nerves and blood vessels.
3. Terms that describe markings include fissure, foramen, meatus, fossa, process. Condyle, head, facet, tuberosity, crest, and spine.

Divisions of the Skeletal System:
The Axial and the Appendicular Skeleton

1. The axial skeleton consists of bones arranged along the longitudinal axis. The parts of the axial skeleton are the skull, hyoid bone, auditory ossicles, vertebral column, sternum, and ribs.
   1. Skull:
      1. The skull consists of the cranium and the face. It is composed of 22 bones.
      2. Sutures are immovable joints between bones of the skull. Examples are coronal, sagittal, lambdoidal, and squamosal sutures.
      3. Fontanels are membrane-filled spaces between the cranial bones of fetuses and infants. The major fontanels are the anterior, posterior, anterolaterals, and posterolaterals.
      4. The 8 cranial bones include the frontal, parietal (2), temporal (2), occipital, sphenoid, and ethmoid.
      5. The 14 facial bones are the nasal (2), maxillae (2), zygomatic (2), mandible, lacrimal (2), palatine (2), inferior nasal conchae (2), and vomer.
      6. Paranasal sinuses are cavities in bones of the skull that communicate with the nasal cavity. They are lined by mucous membranes. The cranial bones containing the paranasal sinuses are the frontal, sphenoid, ethmoid, and maxilla.
      7. The foramina of the skull bones provide passages for nerves and blood vessels.
   2. Hyoid Bone:
      1. The hyoid bone is a U-shaped bone that does not articulate with any other bone.
      2. It supports the tongue and provides attachment for some of its muscles.
   3. Vertebral Column:
      1. The vertebral column, the sternum, and the ribs constitute the skeleton of the trunk.
      2. The bones of the adult vertebral column are the cervical vertebrae (7), thoracic vertebrae (12), lumbar vertebrae (5), the sacrum (5, fused) and the coccyx (4, fused).
      3. The vertebral column contains primary curves (thoracic and sacral) and secondary curves (cervical and lumbar). These curves give strength, support, and balance.
      4. The vertebra are similar in structure, each consisting of a body, vertebral arch, and seven processes. Vertebra in the different regions of the column vary in size, shape, and detail.
   4. Thorax:
      1. The thoracic skeleton consists of the sternum, the ribs and costal cartilages, and the thoracic vertebrae.
      2. The thorax protects vital organs in the chest area.
   5. Disorders - Homeostatic Imbalances:
      1. Protrusion of the nucleus pulposus of an intervertebral disc posteriorly or into an adjacent vertebral body is called a herniated (slipped) disc.
      2. Exaggeration of a normal curve of the vertebral column is called a curvature. Examples include scoliosis, kyphosis, and lordosis.
      3. The imperfect union of the vertebral laminae at the midline, a congenital defect, is referred to as spina bifida.
      4. Fractures of the vertebral column most often involve T 12, L l, and L 2.
2. The appendicular skeleton consists of the bones of the girdles and the upper and lower extremities. The parts of the appendicular skeleton are the shoulder girdles, the bones of the upper extremities, the pelvic girdle, and the bones of the lower extremities.
   • Pectoral (Shoulder) Girdles:
     1. Each pectoral or shoulder girdle consists of a clavicle and scapula.
     2. Each attaches an upper extremity to the trunk.
   • Upper Extremities:
     1. The bones of each upper extremity include the humerus, ulna, radius, carpals, metacarpals, and phalanges.
     2. The carpals are the: Lunate (semilunar), Hamate (Unciform), Triangular (Triquetrum), Pisiform, Schaphoid (Navicular), Capitate, Trapezoid (Lesser multangular), and Trapezium (Greater Multangular).
   • Pelvic Girdle:
     1. The pelvic girdle consists of two coxal bones hipbones.
     2. It attaches the lower extremities to the trunk at the sacrum.
     3. 3. Each coxal bone consists of three fused components-ilium, pubis, and ischium.
   • Lower Extremities:
     1. The bones of each lower extremity include the femur, tibia, fibula, tarsals, metatarsals, and phalanges.
     2. The tarsals are: Calcaneus, Talus, Navicular, Cuboid, Lateral Cuneiform Intermediate Cuneiform, and Medial Cuneiform.
     3. The bones of the foot are arranged in two arches, the longitudinal arch and the transverse arch, to provide support and leverage.

Male and Female Skeletons:

1. The male bones are generally larger and heavier than female bones and have more prominent markings for muscle attachment.
2. The female pelvis is adapted for pregnancy and childbirth.

Articulations:

1. A joint or articulation is a point of contact between two or more bones.
2. Functional classification of joints is based on the degree of movement permitted. Joints may be synarthroses (Nonmovable), amphiarthroses (Slightly Movable), or diarthroses ( Freely Movable).
3. Structural classification is based on the presence of a joint cavity and type of connecting tissue. Structurally, joints are classified as fibrous, cartilaginous, or synovial.

Fibrous Joints:

1. Bones held by fibrous connective tissue, with no joint cavity, are fibrous joints.
2. These joints include immovable sutures (found in the skull), slightly movable syndesmoses (such as the tibiofibular articulation), and immovable gomphoses (roots of teeth in alveoli of mandible and maxilla).

Cartilaginous Joints:

1. 1. Bones held together by cartilage, with no joint cavity, are cartilaginous joints.
2. 2. These joints include immovable synchondroses united by hyaline cartilage (temporary cartilage between diaphysis and epiphyses) and partially movable symphyses united by fibrocartilage (the symphysis pubis).

Synovial Joints:

1. Synovial joints contain a joint (synovial) cavity, articular cartilage, and a synovial membrane; some also contain ligaments, articular discs, and bursae.
2. All synovial joints are freely movable.
3. Movements at synovial joints are limited by the apposition of soft parts, tension of ligaments, and muscle tension.
4. Types of movements at synovial joints include gliding movements, angular movements, rotation, circumduction, inversion and eversion, protraction and retraction, supination and pronation, and elevation and depression.
5. Types of synovial joints include gliding joints (wrist bones), hinge joints (elbow), pivot joints (radioulnar), ellipsoidal joints (radiocarpal), saddle joints (carpometacarpal), and ball-and-socket joints (shoulder and hip).
6. A joint may be described according to the number of planes of movement it allows as nonaxial, biaxial, or triaxial.

Selected Articulations of the Body:

1. The humeroscapular (shoulder joint) is formed by the humerus and scapula.
2. The coxal (hip) joint is formed by the femur and coxal bone.
3. The tibiofemoral (knee) joint is formed by the patella and femur and by the tibia and femur.

Disorders - Homeostatic Imbalances:

1. Rheumatism is a painful state of supporting body structures such as bones, ligaments, tendons, joints, and muscles.
2. Arthritis refers to several disorders characterized by inflammation of joints, often accompanied by stiffness of adjacent structures.
3. Rheumatoid arthritis (RA) refers to inflammation of a joint accompanied by pain, swelling, and loss of function.
4. Osteoarthritis is a degenerative joint disease characterized by deterioration of articular cartilage and spur formation.
5. Gouty arthritis is a condition in which sodium urate crystals are deposited in the soft tissues of joints and eventually destroy the tissues.
6. Bursitis is an acute or chronic inflammation of bursae.
7. A dislocation, or luxation, is a displacement of a bone from its joint; a partial dislocation is called subluxation.
8. A sprain is the forcible wrenching or twisting of a joint with partial rupture to its attachments without dislocation, while a strain is the stretching of a muscle.

The Muscular System:

Characteristics of Muscle tissue:

1. Excitability is the property of receiving and responding to stimuli.
2. Contractility is the ability to shorten and thicken, contract.
3. Extensibility is the ability to be stretched or extended.
4. Elasticity is the ability to return to original shape after contraction or extension.

Functions:

1. Through contraction, muscle tissue performs the three important functions of motion, maintenance of posture, and heat production.

Types:

1. Skeletal muscle tissue is attached to bones. It is striated and voluntary.
2. Visceral muscle tissue is located in viscera. It is nonstriated (smooth) and involuntary.
3. Cardiac muscle tissue forms the walls of the heart. It is striated and involuntary.

Skeletal Muscle Tissue:

1. The term fascia is applied to a sheet or broad band of fibrous connective tissue underneath the skin or around muscles and organs of the body. There are three types of fascia: superficial, deep, and subserous.
2. Connective tissue components are epimysium, covering the entire muscle; perimysium, covering fasciculi; and endomysium, covering individual fibers.
3. Tendons and aponeuroses are extensions of connective tissue beyond the muscle cells to attach the muscle to bone or other muscle.
4. Nerves convey impulses for muscular contraction.
5. Blood provides nutrients and oxygen for contraction.
6. Skeletal muscle consists of fibers covered by a sarcolemma. The fibers contain sarcoplasm, nuclei, sarcoplasmic reticulum, and T tubules. Muscle fibers are individual muscle cells.
7. Each fiber contains myofibrils that consist of thin and thick myofilaments. The myofilaments are compartmelitalized into sarcomeres.
8. Thin myofilaments are composed of actin, tropomyosin, and troponin; thick myofilaments consist of myosin.

Contraction - Sliding Filament Theory:

1. A nerve impulse travels over the sarcolemma and enters the T tubules and sarcoplasmic reticulum.
2. The nerve impulse leads to the release of calcium ions from the sarcoplasmic reticulum, triggering the contractile process.
3. Actual contraction is brought about when the thin myofilaments of a sarcomere slide toward each other.

The Motor Unit:

1. A motor neuron transmits the stimulus to a skeletal muscle for contraction.
2. The region of the sarcolemma under the terminal branch of an axon of a motor neuron that is specialized to receive the nerve impulse is the motor end plate.
3. The area of contact between a motor neuron and muscle fiber is a neuromuscular, or myoneural, junction.
4. A motor neuron and the muscle fibers it stimulates form a motor unit.

Physiology of Contraction:

1. When a nerve impulse reaches the motor end plate, the neuron releases acetylcholine, which transmits the impulse to the motor end plate and then into the T tubules and sarcoplasmic reticulum.
2. This releases calcium ions that activate myosin, catalyzing the breakdown of ATP, and bind tropomyosin-troponin complex, so that actin of thin myofilaments can attach to myosin cross bridges of thick myofilaments.
3. The energy released from the breakdown of ATP causes the sliding of the myofilaments.

Energy for Contraction:

1. The immediate direct source of energy for muscle contraction is ATP.
2. A reserve supply of ATP may be built up by storage of excess in thick myofilaments or by anaerobic combination with creatine to form creatine phosphate, which breaks down to produce ATP when muscles contract strenuously.

All-or-Nothing Principle:

1. Muscle fibers of a motor unit contract to their fullest extent or not at all.
2. The weakest stimulus capable of causing contraction is a liminal, or threshold, stimulus.
3. A stimulus not capable of inducing contraction is a subliminal, or subthreshold, stimulus.

Kinds of Contractions:

1. The various kinds of contractions are twitch, treppe, tetanus, isotonic, and isometric.
2. A record of a contraction is called a myogram. The refractory period is the time right after a contraction when a muscle has temporarily lost excitability. Skeletal muscles have a short refractory period. Cardiac muscle has a long refractory period.
3. Summation of twitches is the increased strength of a contraction resulting from the application of a second stimulus before the muscle has completely relaxed after a previous stimulus.

Muscle Tone:

1. A sustained partial contraction of portions of a skeletal muscle results in muscle tone.
2. Tone is essential for maintaining posture.
3. Flaccidity is a condition of less than normal tone. Atrophy is a wasting away or decrease in size; hypertrophy is an enlargement or overgrowth.

Types of Muscle Fibers:

1. The duration of contraction of various muscles of the body varies with the functions of the muscles in maintaining homeostasis.
2. Fast or white muscles have an extensive sarcoplasmic reticulum.
3. Slow or red muscles have smaller fibers, more blood capillaries, and a large amount of myoglobin.

Cardiac Muscle Tissue:

1. This muscle is found only in the heart. It is striated and involuntary.
2. The cells are quadrangular and usually contain a single centrally placed nucleus.
3. Compared to skeletal muscle tissue, cardiac muscle tissue has more sarcoplasm, more mitochondria, less well-developed sarcoplasmic reticulum, and larger T tubules. Myofilaments are not arranged in discrete myofibrils.
4. The fibers branch freely to form two continuous networks, each of which contracts as a functional unit.
5. Intercalated discs provide strength and aid impulse conduction.

Smooth Muscle Tissue:

1. Smooth muscle is nonstriated and involuntary.
2. Visceral smooth muscle is found in the walls of viscera. The fibers are arranged in a network. Individual cells are generally spindle shaped.
3. Multiunit smooth muscle is found in blood vessels and the eye. The fibers operate singly rather than as a unit.

Homeostasis:

1. Oxygen debt is the amount of O2 needed to convert accumulated lactic acid into CO2 and H20. It occurs during strenuous exercise and is paid back by continuing to breathe rapidly after exercising. Unit it is paid back, the homeostasis between muscular activity and oxygen requirements is not restored.
2. Muscle fatigue results from diminished availability of oxygen and toxic effects of carbon dioxide and lactic acid built up during exercise.
3. The heat given off during muscular contraction maintains the homeostasis of body temperature.

Disorders - Homeostatic Imbalances:

1. Fibrosis is the formation of fibrous tissue where it normally does not exist; it frequently occurs in damaged muscle tissue.
2. Fibrositis is an infiammation of fibrous tissue. If it occurs in the lumbar region, it is called lumbago.
3. "Charleyhorse" refers to pain, tenderness, and stiffness of joints, muscles, and related structures in the thigh.
4. Muscular dystrophy is a hereditary disease of muscles characterized by degeneration of individual muscle cells.
5. Myasthenia gravis is a disease characterized by great muscular weakness and fatigability resulting from improper neuromuscular transmission.
6. Abnormal contractions include spasms, cramps, convulsions, fibrillations. and tics.

How Skeletal Muscles Produce Movement:

1. Skeletal muscles produce movement by pulling on bones.
2. The attachment to the stationary bone is the origin. The attachment to the movable bone is the insertion.
3. Bones serve as levers and joints as fulcrums. The lever is acted on by two different forces: resistance and effort.
4. Levers are categorized into three types-first-class, second-class, and third-class-according to the position of the fulcrum, effort, and resistance on the lever.
5. Fascicular arrangements include parallel, convergent, pennate, and circular.
6. The agonist or prime mover produces the desired action. The antagonist produces an opposite action. The synergist assists the agonist bv reducing unnecessary movement.

Naming Skeletal Muscles:

1. Skeletal muscles are named on the basis of distinctive criteria: direction of fibers, location, size, number of origins (or heads), shape, origin and insertion, and action.

Intramuscular Injections:

1. 1. Advantages of intramuscular injections are prompt absorption, use of larger doses than can be given cutaneously, and minimal irritation.
2. 2. Common sites for intramuscular injections are the buttock, lateral side of the thigh, and deltoid region of the arm.

The Nervous System

The Nervous System:

1. The nervous system controls and integrates all body activities by sensing changes, interpreting them, and reacting to them.
2. The central nervous system consists of the brain and spinal cord.
3. The peripheral nervous system is classified into an afferent system and an efferent system.
4. The efferent system is subdivided into a somatic nervous system and an autonomic nervous system.
5. The somatic nervous system consists of efferent neurons that conduct impulses from the central nervous system to skeletal muscle tissue.
6. The autonomic nervous system contains efferent neurons that convey impulses from the central nervous system to smooth muscle tissue. cardiac muscle tissue. and glands.

Histology:

• Neuroglia:
  1. Neuroglia are specialized tissue cells that support neurons, attach neurons to blood vessels, produce the myelin sheath, and carry out phagocytosis.
  2. Neuroglial cells include astrocytes, oligodendrocytes, microglia, and ependyma.
• Neurons:
  1. Neurons, or nerve cells, consist of a perikaryon or cell body, dendrites that pick up stimuli and convey impulses to the cell body, and usually a single axon. The axon transmits impulses from the neuron to the dendrites or cell body of another neuron or to an effector organ of the body.
  2. On the basis of structure, neurons are multipolar, bipolar, and unipolar.
  3. On the basis of function, sensory (afferent) neurons transmit impulses to the central nervous system; association neurons transmit impulses to other neurons, including motor neurons; and motor (efferent) neurons transmit impulses to effectors.

Physiology:

Regeneration:

1. Around the time of birth, the nerve cell body loses its mitotic apparatus and is no longer able to divide.
2. Nerve fibers (axis cylinders) that have a neurilemma are capable of regeneration. If, however a nerve cell body is distorted there will be no regeneration.

Nerve Impulse:

1. The nerve impulse is the body's quickest way of controlling and maintaining homeostasis.
2. The membrane of a nonconducting neuron is positive outside and negative inside due to the operation of the sodium-potassium pump. This difference in charge is called a resting potential, and the membrane is said to be polarized.
3. When a stimulus causes the inside of the cell membrane to become positive and the outside negative, the membrane is said to have an action potential, which travels from point to point along the membrane. The traveling action potential is a nerve impulse. The ability of a neuron to respond to a stimulus and convert it into a nerve impulse is called excitability.
4. Restoration of the resting potential is called repolarization. The period of time during which the membrane recovers is called the refractory period.
5. According to the all-or-nothing principle, if a stimulus is strong enough to generate an action potential, the impulse travels at a constant and maximum strength for the existing conditions.
6. Nerve impulse conduction in which the impulse jumps from node to node is called salitatory conduction.
7. Fibers with larger diameters conduct impulses faster than those with smaller diameters.

Conduction Across Synapses:

1. Impulse conduction can occur from one neuron to another or from a neuron to an effector.
2. The junction between neurons is called a synapse.
3. At a synapse there is only one-way impulse conduction from a presynaptic axon to a postsynaptic dendrite, cell body, or axon hillock.
4. An excitatory transmitter-receptor interaction is one that can lower (make less negative) the postsynaptic neuron's membrane potential so that a new impulse can be generated across the synapse.
5. An inhibitory transmitter-receptor interaction is one that can raise (make more negative) the postsynaptic neuron's membrane potential and thus inhibit an impulse at a synapse.
6. It is thought that the transmitter that causes excitation in a major portion of the central nervous system is acetylcholine. An enzyme called acetylcholinesterase inactivates acetylcholine.

Grouping of Neural Tissue:

1. White matter is an aggregation of myelinated axons and associated neuroglia.
2. Gray matter is a collection of nerve cell bodies and dendrites or unmyelinated axons along with associated neuroglia.
3. A nerve is a bundle of nerve fibers outside the central nervous system.
4. A ganglion is a collection of cell bodies outside the central nervous system.
5. A tract is a bundle of fibers of similar function in the central nervous system.
6. A nucleus is a mass of nerve cell bodies and dendrites in the gray matter of the brain and spinal cord.
7. A horn or column is an area of gray matter in the spinal cord.

Spinal Cord:

General Features:

1. The spinal cord begins as a continuation of the medulla oblongata and terminates at about the second lumbar vertebra.
2. It contains cervical and lumbar enlargements which serve as points of origin for nerves to the extremities.
3. The tapered portion of the spinal cord is the conus medullaris, from which arise the filum terminale and cauda equina.
4. The spinal cord is partially divided into right and left sides by the anterior median fissure and posterior median sulcus.
5. The gray matter in the spinal cord is divided into horns and the white matter into funiculi or columns.
6. In the center of the spinal cord is the central canal, which runs the length of the spinal cord and contains cerebrospinal fluid.
7. There are ascending (sensory) tracts and descending (motor) tracts.

Protection and Coverings:

1. The spinal cord is protected by the vertebral canal, meninges, cerebrospinal fluid, and vertebral ligaments.
2. The meninges are three coverings that run continuously around the spinal cord and brain: dura mater, arachnoid and pia mater.
3. Removal of cerebrospinal fluid from the subarachnoid space or ventricle is called a spinal (lumbar) puncture. The procedure is used to diagnose pathologies and to introduce antibiotics.

Structure in Cross Section:

1. Parts of the spinal cord observed in cross section are the gray commissure; central canal; anterior, posterior, and lateral gray horns; anterior, posterior, and lateral white columns; and ascending and descending tracts.
2. The spinal cord conveys sensory and motor information by way of the ascending and descending tracts, respectively.

Functions:

1. A major function of the spinal cord is to convey sensory impulses from the periphery to the brain and to conduct motor impulses from the brain to the periphery.
2. Another function is to serve as a reflex center. The posterior root, posterior root ganglion, and anterior root are involved in conveying an impulse.
3. A reflex arc is the shortest route that can be taken by an impulse from a receptor to an effector. Its basic components are a receptor, a sensory neuron, a center, a motor neuron, and an effector.
4. A reflex is a quick, involuntary response to a stimulus that passes along a reflex arc. Reflexes represent the body's principal mechanisms for responding to changes in the internal and external environment.
5. Somatic spinal reflexes include the stretch reflex, tendon reflex, flexor reflex, and crossed extensor reflex.
6. A two-neuron or monosynaptic reflex arc contains one sensory and one motor neuron. A stretch reflex, such as the patellar reflex, is an example.
7. A polysynaptic reflex arc contains a sensory, association, and motor neuron. A withdrawal or flexor reflex and a crossed extensor reflex are examples.
8. Stretch and flexor reflexes are ipsilateral. The crossed extensor reflex is controlateral.
9. Among clinically important somatic reflexes are the patellar reflex, the Achilles reflex, the Babinski sign, and the abdominal reflex.

Spinal Nerves:

• The 31 pairs of spinal nerves are named and numbered according to the region and level of the spinal cord from which they emerge.
• Composition and Coverings:
  1. Spinal nerves are attached to the spinal cord by means of a posterior root and an anterior root. All spinal nerves are mixed function (motor and sensory).
  2. Spinal nerves are covered by endoneurium, perineunum, and epineurium.
• Distribution:
  1. 1. Branches of a spinal nerve include the dorsal ramus, ventral ramus, meningeal branch, and rami communicantes.
  2. 2. The ventral rami of spinal nerves, except for T 2-T 11, form networks of nerves called plexuses.
  3. 3. Emerging from the plexuses are nerves bearing names that are often descriptive of the general regions they supply or the course they take.
  4. 4. The principal plexuses are called the cervical, brachial, lumbar, and sacral plexuses.
  5. 5. Nerves T 2-T 11 do not form plexuses and are called intercostal nerves. They are distributed directly to the structures they supply in the ntercostals spaces.
• Dermatomes:
  1. 1. All spinal nerves except Cl innervate specific, constant segments of the skin. The skin segments are called dermatomes.
  2. 2. Knowledge of dermatomes helps a physician to determine which segment of the spinal cord or spinal nerve is malfunctioning.

Disorders - Homeostatic Imbalances:

1. Complete or partial severing of the spinal cord is called transection. It may result in quadriplegia or paraplegia. Partial transection is followed by a period of loss of reflex activity called areflexia.
2. Following peripheral nerve damage, repair is accomplished by an axon reaction, Wallerian degeneration, and regeneration.
3. Inflammation of nerves is known as neuritis.
4. Neuritis of the sciatic nerve and its branches is called sciatica.
5. Shingles is acute infection of peripheral nerves.

The Brain:

1. Embryological Development:
   1. 1. During embryological development, brain vesicles are formed and serve as forerunners of various parts of the brain.
   2. 2. The diencephalon develops into the thalamus and hypothalamus, the telencephalon forms the cerebrum, the mesencephalon develops into the midbrain, the myelencephalon forms the medulla, and the metencephalon develops into the pons and cerebellum.
2. Protection and Coverings:
   1. 1. The principal parts of the brain are the brain stem, diencephalon, cerebrum, and cerebellum.
   2. 2. The brain is protected by the cranial bones, cranial meninges, and cerebrospinal fluid
3. Cerebrospinal Fluid:
   1. Cerebrospinal fluid is formed in the choroid plexuses and circulates through the subarachnoid space, ventricles, and central canal. Most of the fluid is absorbed by the arachnoid villi of the superior sagittal sinus.
   2. Cerebrospinal fluid protects by serving as a shock absorber. It also circulates nutritive substances from the blood.
   3. The accumulation of cerebrospinal fluid in the head is called hydrocephalus. If the fluid accumulates in the ventricles, it is called internal hydrocephalus. If it accumulates in the subarachnoid space, it is called external hydrocephalus.
4. Blood Supply to the Brain:
   1. 1. The blood supply to the brain is via the circle of Willis.
   2. 2. Any interruption of the oxygen supply to the brain can result in weakening, permanent damage, or death of brain cells. Interruption of the mother's blood supply to a child during childbirth before it can breathe may result in paralysis, mental retardation, epilepsy, or death.
   3. 3. Glucose deficiency may produce dizziness, convulsions, and unconsciousness.
   4. 4. The blood-brain barrier (BBB) is a concept that explains the differential rates of passage of certain materials from the blood into the brain.
5. The Brain Stem:
   1. 1. The medulla oblongata is continuous with the upper part of the spinal cord. It contains nuclei that are reflex centers for regulation of heart rate, respiratory rate, vasoconstriction, swallowing, coughing, vomiting, sneezing, and hiccuping. It also contains the nuclei of origin for cranial nerves VIII (cochlear and vestibular branches) through XII.
   2. 2. The pons is superior to the medulla. It connects the spinal cord with the brain and links parts of the brain with one another. It relays impulses from the cerebral cortex to the cerebellum related to voluntary skeletal movements. It contains the nuclei for cranial nerves V through VII and the vestibular branch of VIII. The reticular formation of the pons contains the pneumotaxic center. which helps control respiration.
   3. 3. The midbrain connects the pons and diencephalon. It conveys motor impulses from the cerebrum to the cerebellum and cord, sensory impulses from cord to thalamus, and regulates auditory and visual reflexes. It also contains the nuclei of origin for cranial nerves III and IV.
6. The Diencephalon:
   1. 1. The diencephalon consists of the thalamus and hypothalamus.
   2. 2. The thalamus is superior to the midbrain and contains nuclei that serve as relay stations for all sensory impulses, except smell, to the cerebral cortex. It also registers conscious recognition of pain and temperature and some awareness of crude touch and pressure.
   3. 3. The hypothalamus is inferior to the thalamus. It controls the autonomic nervous system, connects the nervous and endocrine systems, controls body temperature, regulates food and fluid intake, and maintains the waking state and sleep patterns.
7. The Cerebrum:
   1. 1. The cerebrum is the largest part of the brain. Its cortex contains convolutions, fissures, and sulci.
   2. 2. The cerebral lobes are named the frontal, parietal, temporal, and occipital.
   3. 3. The white matter is under the cortex and consists of myelinated axons running in three principal directions.
   4. 4. The basal ganglia are paired masses of gray matter in the cerebral hemispheres. They help to control muscular movements.
   5. 5. The limbic system is found in the cerebral hemispheres and diencephalon. It functions in emotional aspects of behavior and memory.
   6. 6. The motor areas of the cerebral cortex are the regions that govern muscular movement. The sensory areas are concerned with the interpretation of sensory impulses. The association areas are concerned with emotional and intellectual processes.
   7. 7. Brain waves generated by the cerebral cortex are recorded as an EEG. They may be used to diagnose epilepsy, infections, and tumors.
8. Brain Lateralization:
   1. 1. Recent research indicates that the two hemispheres of the brain are not bilaterally symmetrical, either anatomically or functionally.
   2. 2. The left hemisphere is more important for right-handed control, spoken and written language, numerical and scientific skills, and reasoning.
   3. 3. The right hemisphere is more important for left-handed control, musical and artistic awareness, space and pattern perception, insight, imagination, and generating mental images of sight, sound, touch, taste, and smell.
9. The Cerebellum:
   1. 1. The cerebellum occupies the inferior and posterior aspects of the cranial cavity. It consists of two hemispheres and a central, constricted vermis.
   2. 2. It is attached to the brain stem by three pairs of cerebellar peduncles.
   3. 3. The cerebellum functions in the coordination of skeletal muscles and the maintenance of normal muscle tone and body equilibrium.
10. Transmitter Substances in the Brain:
    1. 1. Over 40 different substances are known or suspected transmitter substances in the brain that can facilitate, excite, or inhibit postsynaptic neurons.
    2. 2. Examples of transmitter substances include acetylcholine, norepinephrine, dopamine, serotonin, glutamic acid, aspartic acid, gamma aminobutyric acid, and glycine.
    3. 3. Peptide chemical messengers that act as natural pain killers in the body are enkephalins, endorphins, and dynorphin.
    4. 4. Other peptides serve as hormones or other regulators of physiological responses. Examples include angiotensin, cholecystokinin, and regulating factors produced by the hypothalamus.
11. The Cranial Nerves:
    1. Twelve pairs of cranial nerves originate from the brain. The pairs are named primarily on the basis of distribution and numbered by order of attachment to the brain. The cranial nerves and their major functions are:
       1. 1. Olfactory - The sense of smell.
       2. Optic - The sense of vision.
       3. Oculomotor - Motor function of eye muscles.
       4. Trochlear - Motor function of eye muscles.
       5. Trigeminal - Sensory function. Scalp, forehead, nose, upper eyelid, cornea, Palate, upper jaw, upper teeth, lower jaw, lower teeth, etc. Motor function, muscles of mastication.
       6. Abduscens - Motor function of eye muscles.
       7. . Facial - Sensory, taste. Motor function, muscles of facial expression, etc.
       8. Vestibulocochlear - Sensory, hearing and balance.
       9. Glossopharyngeal - Sensory, taste. Motor, pharyngeal muscles.
       10. Vagus - Sensory, inferior pharynx, larynx, thoracic and abdominal organs. Motor, soft palate, larangeal muscles, tongue muscles.
       11. Accessory - Motor, Soft palate, pharynx, some neck and shoulder muscles.
       12. Hypoglossal - Motor, Tongue muscles.
12. Disorders - Homeostatic Imbalances:
    1. Poliomyelitis is a viral infection that results in paralysis.
    2. Cerebral palsy refers to a group of motor disorders caused by damage to motor centers of the cerebral cortex, cerebellum, or basal ganglia during fetal development, childbirth, or early infancy.
    3. Parkinsonism is a progressive degeneration of the basal ganglia of the cerebrum resulting in insufficient dopamine.
    4. Multiple sclerosis (MS) is the destruction of myelin sheaths of the neurons of the central nervous system. Impulse transmission is interrupted.
    5. Epilepsy results from irregular electrical discharges of brain cells and may be diagnosed by an EEG. Depending on the form of the disease, the victim experiences degrees of motor, sensory, or psychological malfunction.
    6. Cerebrovascular accidents (CVAs), also called strokes, are brain tissue destruction due to hemorrhage, thrombosis, or atherosclerosis.
    7. Dyslexia involves an inability of an individual to comprehend written language.
    8. Tay-Sachs disease is an inherited disorder that involves neurological degeneration of the CNS because of excessive amounts of ganglioside Gm2.
    9. Headaches are of two types: intracranial and extracranial.
    10. Irritation of the trigeminal nerve is known as trigeminal neuralgia.
    11. Rabies is an acute viral infection that produces muscle spasms and encephalitis.
    12. Reye’s syndrome (RS) is characterized by vomiting, brain dysfunction, and liver damage.
    13. Senility (dementia) is a disorder of the elderly that involves widespread intellectual impairment, personality changes, and sometimes delirium.

Sensations:

1. Sensation is a state of awareness of external and internal conditions of the body.
2. The prerequisites for sensation are reception of a stimulus, conversion of the stimulus into a nerve impulse by a receptor, conduction of the impulse to the brain, and translation of the impulse into a sensation by a region of the brain.

Characteristics:

1. Projection occurs when the brain refers a sensation to the point of stimulation.
2. Adaptation is the loss of sensation even though the stimulus is still applied.
3. An afterimage is the persistence of a sensation even though the stimulus is removed.
4. Modality is the property by which one sensation is distinguished from another.

Classification of Receptors:

1. According to location, receptors are classified as exteroceptors, visceroceptors, and proprioceptors.
2. On the basis of type of stimulus detected, receptors are classified as mechanoreceptors, thermoreceptors, nociceptors, electromagnetic receptors, and chemoreceptors.
3. In terms of simplicity or complexity, simple receptors are associated with general senses and complex receptors are associated with special senses.

General Senses - Cutaneous Sensations:

1. Cutaneous sensations include tactile sensations (touch, pressure, vibration), thermoreceptive sensations (heat and cold), and pain. Receptors for these sensations are located in the skin, connective tissues, and the ends of the gastrointestinal tract.
2. Receptors for touch are root hair plexuses, free nerve endings, Merkel's discs, Meissner's corpuscles, and end organs of Ruffini. Receptors for pressure are free nerve endings, end organs of Ruffini, and Pacinian corpuscles. Receptors for vibration are Meissner's corpuscles and Pacinian corpuscles.
3. Pain receptors are located in nearly every body tissue.
4. Two kinds of pain recognized in the parietal lobe of the cortex are somatic and visceral.
5. Referred pain is felt in the skin near or away from the organ sending pain impulses.
6. Phantom pain is the sensation of pain in a limb that has been amputated.
7. Pain impulses may be inhibited by drugs, surgery, and acupuncture.

Proprioceptive (Position Sense) Sensations:

1. Receptors located in muscles, tendons, and joints convey impulses related to muscle tone, movement of body parts, and body position.
2. The receptors include joint kinesthetic receptors, muscle spindles, and tendon organs.

Levels of Sensation:

1. Sensory fibers terminating in the lower brain stem bring about far more complex motor reactions than simple spinal reflexes.
2. When sensory impulses reach the lower brain stem, they cause subconscious motor reactions.
3. Sensory impulses that reach the thalamus can be localized crudely in the body.
4. When sensory impulses reach the cerebral cortex, we experience precise localization

Sensory Pathways:

1. Sensory information from all parts of the body terminates in a specific area of the somatosensory cortex.
2. In the posterior column pathway and the spinothalamlc pathway there are first-order, second-order, and third-order neurons.
3. The neural pathway for pain and temperature is the lateral spinothalamic pathway.
4. The neural pathway for crude touch and pressure is the anterior spinothalamic pathway.
5. The neural pathway for light touch, proprioception, and vibration is the posterior column pathway.
6. The pathways to the cerebellum are the anterior and posterior spinocerebellar tracts.

Motor Pathways:

1. The muscles of all parts of the body are controlled by a specific area of the motor cortex.
2. Voluntary motor impulses are conveyed from the brain through the spinal cord along the pyramidal pathways and the extrapyramidal pathways.
3. Pyramidal pathways include the lateral corticospinal, anterior corticospinal, and corticobulbar tracts.
4. Major extrapyramidal tracts are the rubrospinal, tectospinal, and vestibulospinal tracts.

Integrative Functions:

1. Memory is defined as the ability to recall thoughts; it consists of activated and long-term components.
2. Sleep and wakefulness are integrative functions that are controlled by the reticular activating system (RAS).
3. Nonrapid eye movement (NREM) sleep consists of four stages identified by EEG recordings.
4. Most dreaming occurs during rapid eye movement (REM) sleep.

Somatic Efferent and Autonomic Nervous Systems:

1. The autonomic nervous system, or visceral efferent nervous system, regulates visceral activities, that is, activities of smooth muscle, cardiac muscle, and glands.
2. It usually operates without conscious control.
3. It is regulated by centers in the brain, in particular by the cerebral cortex, the hypothalamus, and the medulla oblongata.
4. The somatic efferent nervous system produces conscious movement in skeletal muscles.

Structure of the Autonomic Nervous System:

1. The autonomic nervous system consists of visceral efferent neurons organized into nerves, ganglia, and plexuses.
2. It is entirely motor. All autonomic axons are efferent fibers.
3. Efferent neurons are preganglionic (with myelinated axons) and postganglionic (with unmyelinated axons).
4. The autonomic system consists of two principal divisions: sympathetic (thoracolumbar) and parasympathetic (craniosacral).
5. Autonomic ganglia are classified as sympathetic trunk ganglia (on sides of spinal column), prevertebral ganglia (anterior to spinal column), and terminal ganglia (near or inside visceral effectors).

Physiology:

1. Autonomic fibers release chemical transmitters at synapses. On the basis of the transmitter produced, these fibers may be classified as cholinergic or adrenergic.
2. Cholinergic fibers release acetylcholine. Adrenergic fibers produce norepinephrine.
3. Sympathetic responses are widespread and, in general, concerned with energy expenditure. Parasympathetic responses are restricted and are typically concerned with energy restoration and conservation.

Visceral Autonomic Reflexes:

1. A visceral autonomic reflex adjusts the activity of a visceral effector.
2. A visceral autonomic reflex arc consists of a receptor, afferent neuron, association neuron, visceral efferent preganglionic neuron, visceral efferent postganglionic neuron, and visceral effector.

Control by Higher Centers:

1. The hypothalamus controls and integrates the autonomic nervous system. It is connected to both the sympathetic and the parasympathetic divisions.
2. Biofeedback is a process in which people learn to monitor visceral functions and to control them consciously. It has been used to control heart rate, to alleviate migraine headaches, and to make childbirth easier.
3. Yoga is a higher consciousness achieved through a fully rested and relaxed body and a fully awake and relaxed mind.
4. Transcendental meditation (TM) produces the following physiological responses: decreased oxygen consumption and carbon dioxide elimination, reduced metabolic rate, decrease in heart rate, increase in the intensity of alpha brain waves, a sharp decrease in the amount of lactic acid in the blood, and an increase in the skin's electrical resistance.

Olfactory Sensations:

1. The receptors for olfaction are in the nasal epithelium.
2. Substances to be smelled must be volatile, water-soluble, and lipid-soluble.
3. Two theories that explain how olfactory cells respond to primary sensations are the chemical theory and physical theory.
4. Adaptation to odors occurs quickly, and the threshold of smell is low.
5. Olfactory cells convey impulses to olfactory nerves, olfactory bulbs, olfactory tracts, and cerebral cortex.

Gustatory (Taste) Sensations:

1. The receptors for gustation are located in taste buds.
2. Substances to be tasted must be in solution in saliva.
3. The four primary tastes are salt, sweet, sour, and bitter.
4. Adaptation to taste occurs quickly, and the threshold varies with the taste involved.
5. Gustatory cells convey impulses to cranial nerves V, VII, IX, and X, medulla, thalamus, and cerebral cortex.

Visual Sensations:

1. Accessory structures of the eyes include the eyebrows, eyelids, eyelashes, and the lacrimal apparatus.
2. The eye is constructed of three coats: (a) fibrous tunic (sclera and cornea), (b) vascular tunic (choroid, ciliary body, and iris), and (c) retina, which contains rods and cones.
3. The anterior cavity contains aqueous humor; the posterior cavity contains vitreous humor.
4. The refractive media of the eye are the cornea, aqueous humor, lens, and vitreous humor.
5. Retinal image formation involves refraction of light, accommodation of the lens, constriction of the pupil, convergence, and inverted image formation.
6. Improper refraction may result from myopia (nearsightedness), hypermetropia (farsightedness), and astigmatism (corneal or lens abnormalities).
7. Rods and cones develop generator potentials and ganglion cells initiate nerve impulses.
8. Impulses from ganglion cells are conveyed through the retina to the optic (II) nerve, the optic chiasma, the optic tract. the thalamus, and the cortex.

Auditory Sensations and Equilibrium:

1. The ear consists of three anatomical subdivisions: (a) the external or outer ear (pinna, external auditory canal, and tympanic membrane), (b) the middle ear (auditory tube, ossicles, oval window, and round window), and (c) the internal or inner ear (bony labyrinth and membranous labyrinth). The internal ear contains the spiral organ, the organ of hearing.
2. Sound waves enter the external auditory canal, strike the tympanic membrane, pass through the ossicles, strike the oval window, set up waves in the perilymph, strike the vestibular membrane and scala tympani, increase pressure in the endolymph, strike the basilar membrane, and stimulate hairs on the spiral organ. A sound impulse is then initiated.
3. Static equilibrium is the orientation of the body relative to the pull of gravity. The maculae of the utricle and saccule are the sense organs of static equilibrium.
4. Dynamic equilibrium is the maintenance of body position in response to movement. The cristae in the semicircular ducts are the sense organs of dynamic equilibrium.

Disorders - Homeostatic Imbalances:

1. Cataract is the loss of transparency of the lens or capsule.
2. Glaucoma is abnormally high intraocular pressure, which destroys neurons of the retina.
3. Conjunctivitis is an inflammation of the conjunctiva.
4. Trachoma is a chronic, contagious inflammation of the conjunctiva.
5. Deafness is the lack of the sense of hearing or significant hearing loss.
6. Labyrinthine disease is basically a malfunction of the inner ear that has a variety of causes.
7. Meniere's syndrome is the malfunction of the inner ear that may cause deafness and loss of equilibrium.
8. Impacted cerumen is an abnormal amount of earwax in the external auditory canal.
9. Otitis media is an acute infection of the middle ear cavity.
10. Motion sickness is a functional disorder precipitated by repetitive angular, linear, or vertical motion.

The Endocrine System and Glands

The Endocrine System and Glands:

1. Both the endocrine and nervous systems assume a role in maintaining homeostasis.
2. Hormones help regulate the internal environment, respond to stress, help regulate growth and development, and contribute to reproductive processes.
3. Exocrine glands (sweat, sebaceous, digestive) secrete their products through ducts into body cavities or onto body surfaces.
4. Endocrine glands secrete hormones into the blood.

Chemistry of Hormones:

1. On the basis of solubility, hormones are classified as water soluble and lipid-soluble.
2. Cells that respond to the effects of hormones are called target cells.

Mechanism of Hormonal Action:

1. Water-soluble hormones exert their effects by interacting with plasma membrane receptors; some utilize cyclic AMP as a second messenger.
2. Lipid-soluble hormones exert their effects by interacting directly with genes.
3. Prostaglandins (PG) can increase or decrease cyclic AMP formation and thus modulate hormone responses that use cyclic AMP.

Control of Hormonal Secretions - Feedback Control:

1. A negative feedback control mechanism prevents overproduction or underproduction of a hormone.
2. Hormone secretions are controlled by levels of circulating hormone itself, nerve impulses, and regulating factors.

Pituitary (Hypophysis):

1. The pituitary is located in the sella turcica of the skull and is differentiated into the adenohypophysis (the anterior lobe and glandular portion) and the neurohypophysis (the posterior lobe and nervous portion).
2. Hormones of the adenohypophysis are released or inhibited by regulating factors produced by the hypothalamus.
3. The blood supply to the adenohypophysis is from the superior hypophyseal arteries.
4. Histologically, the adenohypophysis consists of growth hormone cells that produce growth hormone (GH); prolactin cells that produce prolactin (PRL); TSH cells that secrete thyroid-stimulating hormone (TSH); gonadotroph cells that synthesize follicle-stimulating hormone (FSH) and luteinizing hormone (LH); and corticotroph-lipotroph cells that secrete adrenocorticotropin hormone (ACTH) and melanocyte-stimulating hormone (MSH).
5. GH stimulates body growth through somatomedins and insulinlike growth factors (IGF) and is controlled by GHIF (growth hormone inhibiting factor or somatostatin) and GHRF (growth hormone releasing factor).
6. Disorders associated with improper levels of GH are pituitary dwarfism, giantism, and acromegaly.
7. TSH regulates thyroid gland activities and is controlled by TRF (thyrotropin releasing factor).
8. ACTH regulates the activities of the adrenal cortex and is controlled by CRF (corticotropin releasing factor).
9. FSH regulates the activities of the ovaries and testes and is controlled by GnRF (gonadotropin releasing factor).
10. LH regulates female and male reproductive activities and is controlled by GnRF.
11. PRL helps initiate milk secretion and is controlled by PIF (prolactin inhibiting factor) and PRF (prolactin releasing factor).
12. MSH increases skin pigmentation and is controlled by MRF (melanocyte-stimulating hormone releasing factor) and MIF (melanocyte-stimulating hormone inhibiting factor).
13. The neural connection between the hypothalamus and neurohypophysis is via the hypothalamic-hypophyseal tract.
14. Hormones made by the hypothalamus and stored in the neurohypophysis are oxytocin or OT (stimulates contraction of uterus and ejection of milk) and antidiuretic hormone or ADH (stimulates water reabsorption by the kidneys and arteriole constriction).
15. OT secretion is controlled by uterine distension and sucking during nursing; ADH is controlled primarily by water concentration.
16. A disorder associated with dysfunction of the neurohypophysis is diabetes insipidus.

Thyroid:

1. The thyroid gland is located below the larynx.
2. Histologically, the thyroid consists of thyroid follicles composed of follicular cells, which secrete the thyroid hormones thyroxine (T4) and triiodothyronine (T3), and parafollicular cells, which secrete calcitonin (CT).
3. Thyroid hormones are synthesized from iodine and tyrosine within thyroglobulin and carried in the blood with plasma proteins, mostly thyroxine-binding globulin (TBG).
4. Thyroid hormones regulate the rate of metabolism, growth and development, and the reactivity of the nervous system. Secretion is controlled by TRF.
5. Cretinism, myxedema, exophthalmic goiter, and simple goiter are disorders associated with dysfunction of the thyroid gland.
6. Calcitonin (CT) lowers the blood level of calcium. Secretion is controlled by its own level in blood.
   

Parathyroids:

1. The parathyroids are embedded on the posterior surfaces of the lateral lobes of the thyroid.
2. Histologically, the parathyroids consist of principal and oxyphil cells.
3. Parathyroid hormone (PTH) regulates the homeostasis of calcium and phosphate by increasing blood calcium level and decreasing blood phosphate level. Secretion is controlled by its own level in blood.
4. Tetany and osteitis fibrosa cystica are disorders associated with the parathyroid glands.

Adrenals (Suprarenals):

1. The adrenal glands are located superior to the kidneys. They consist of an outer cortex and inner medulla.
2. Histologically, the cortex is divided into a zona glomerulosa, zona ennin late, and zona reticularis; the medulla consists of chromaffin cells.
3. Cortical secretions are mineralocorticoids, glucocorticoids, and gonadocorticoids.
4. Mineralocorticoids (e.g., aldosterone) increase sodium and water reabsorption and decrease potassium reabsorption. Secretion is controlled by the ennin-angiotensin pathway and blood level of potassium.
5. A dysfunction related to aldosterone secretion is aldosteronism.
6. Glucocorticoids (e.g., cortisol) promote normal metabolism, help resist stress, and serve as antiinflammatories. Secretion is controlled by CRF.
7. Disorders associated with glucocorticoid secretion are Addison’s disease and Cushing’s syndrome.
8. Gonadocorticoids secreted by the adrenal medulla have minimal effects. Excessive production results in adrenogenital syndrome.
9. Medullary secretions are epinephrine and norepinephrine (NE) which produce effects similar to sympathetic responses. They are released under stress.
10. Tumors of medullary chromaffin cells are called pheochromocytomas.

Pancreas:

1. The pancreas is posterior and slightly inferior to the stomach.
2. Histologically, it consists of islets of Langerhans (endocrine cells) and acini (enzyme-producing cells). Three types of cells in the endocrine portion are alpha cells, beta cells, and delta cells.
3. Alpha cells secrete glucagon, beta cells secrete insulin, and delta cells secrete growth hormone inhibiting factor (GHIF) or somatostatin.
4. Glucagon increases blood sugar level. Secretion is controlled by its own level in the blood.
5. Insulin decreases blood sugar level. Secretion is controlled by its own level in the blood.
6. Disorders associated with insulin production are diabetes mellitus and hyperinsulinism.

Ovaries and Testes:

1. Ovaries are located in the pelvic cavity and produce sex hormones related to development and maintenance of female sexual characteristics. menstrual cycle, pregnancy, and lactation.
2. Testes lie inside the scrotum and produce sex hormones related to the development and maintenance of male sexual characteristics.

Pineal (Epiphysis Cerebri):

1. The pineal is attached to the roof of the third ventricle.
2. Histologically, it consists of secretory parenchymal cells called pinealocytes, neuroglial cells, and scattered preganglionic sympathetic fibers. Calcified deposits are referred to as brain sand.
3. It secretes melatonin (possibly regulates reproductive activities by inhibiting gonadotropic hormones) and adrenoglomerulotropin (may stimulate adrenal cortex to secrete aldosterone).

Thymus:

1. The thymus is a bilobed Iymphatic gland located in the superior mediastinum posterior to the sternum and between the lungs.
2. Hormones secreted are: Thymosin, thymic humoral factor (THF), thymic factor (TF), and thymopoietin which promotes the maturation of T cells.

The Cardiovascular System:

Blood:

Physical Characteristics:

1. The cardiovascular system consists of blood, the heart, and blood vessels. The Iymphatic system consists of Iymph, Iymph vessels, and Iymph glands.
2. Physical characteristics of blood include viscosity, 4.5 to 5.5; temperature, 38 degrees C (100.4 degrees F); pH, 7.35 to 7.45; and salinity, 0.85 to 0.90 NaCI. Blood constitutes about 8 percent of body weight.

Functions:

1. Blood transports oxygen, carbon dioxide, nutrients, wastes, hormones, and enzymes.
2. It helps to regulate pH, body temperature, and water content of cells.
3. It prevents excessive fluid loss through clotting.
4. It protects against toxins and microbes.

Components:

1. The formed elements in blood include erythrocytes (red blood cells), leucocytes (white blood cells), and thrombocytes (platelets).
2. Blood cells are formed by a process called hemopoiesis.
3. Red bone marrow (myeloid tissue) is responsible for producing red blood cells, granular leucocytes, and platelets; Iymphoid tissue and myeloid tissue produce agranular leucocytes.

Erythrocytes:

1. Erythrocytes are biconcave discs without nuclei and containing hemoglobin.
2. The function of red blood cells is to transport oxygen and carbon dioxide.
3. Red blood cells live about 120 days. A healthy male has about 5.4 million/mm3 of blood; a healthy female, about 4.8 million/mm3.
4. Erythrocyte formation, called erythropoiesis, occurs in adult red marrow of certain bones.
5. A reticulocyte count is a diagnostic test that indicates the rate of erythropoiesis.
6. A hematocrit measures the percentage of red blood cells in whole blood.

Leucocytes:

1. Leucocytes are nucleated cells. Two principal types are granular (neutrophils, eosinophils, basophils) and agranular (Iymphocytes and monocytes).
2. The general function of leucocytes is to combat inflammation and infection. Neutrophils and monocytes (wandering macrophages) do so through phagocytosis.
3. Eosinophils and basophils are involved in combating allergic reactions.
4. Lymphocytes, in response to the presence of foreign substances called antigens, differentiate into tissue plasma cells which produce antibodies. Antibodies attach to the antigens and render them harmless. This antigen-antibody response combats infection and provides immunity.
5. A differential count is a diagnostic test in which white blood cells are enumerated.
6. White blood cells usually live for only a few hours or a few days. Normal blood contains 5,000 to 9,000/mm3.

Thrombocytes:

1. Thrombocytes are disc-shaped structures without nuclei.
2. They are formed from megakaryocytes and are involved in clotting.
3. Normal blood contains 250,000 to 400,000/mm3.

Plasma:

1. The liquid portion of blood, called plasma, consists of 91.5 percent water and 8.5 percent solutes.
2. Principal solutes include proteins (albumins, globulins, fibrinogen), nonprotein nitrogen (NPN) substances, foods, enzymes and hormones, respiratory gases, and electrolytes

Hemostasis:

1. Hemostasis refers to the prevention of blood loss.
2. It involves vascular spasm, platelet plug formation, and blood coagulation.
3. In vascular spasm, the smooth muscle of a blood vessel wall contracts to stop bleeding.
4. Platelet plug formation involves the clumping of platelets to stop bleeding.
5. A clot is a network of insoluble protein (fibrin) in which formed elements of blood are trapped.
6. The chemicals involved in clotting are known as coagulation factors. There are two kinds: plasma and platelet coagulation factors.
7. Blood clotting involves two pathways: the intrinsic and the extrinsic.
8. Normal coagulation also involves clot retraction (tightening of the clot) and fibrinolysis (dissolution of the clot).
9. Clotting in an unbroken blood vessel is called thrombosis. A thrombus that moves from its site of origin is called an embolus.
10. Anticoagulatants (e.g., heparin) prevent clogging.
11. Clinically important clotting tests are clotting time (time required for blood to coagulate), bleeding time (time required for the cessation of bleeding from a small skin puncture), and prothrombin time (time required for the blood to coagulate, which depends on the amount of prothrombin in the blood sample).

Blood Grouping (Typing):

1. ABO and Rh systems are based on antigen-antibody responses.
2. In the ABO system, agglutinogens (antigens) A and B determine blood type. Plasma contains agglutinins (antibodies) that clump agglutinogens which are foreign to the individual.
3. In the Rh system, individuals whose erythrocytes have Rh agglutinogens are classified as Rh+. Those who lack the antigen are Rh-.
4. A disorder due to Rh incompatibility between mother and fetus is called erythroblastosis fetalis.

Interstitial Fluid:

1. Interstitial fluid bathes body cells, whereas Iymph is found in Iymphatic vessels.
2. These fluids are similar in chemical composition. They differ chemically from plasma in that both contain less protein and a variable number of leucocytes. Like plasma, they contain no platelets or erythrocytes.

Disorders - Homeostatic Imbalances:

1. Anemia is a decreased erythrocyte count or hemoglobin deficiency. Kinds of anemia include nutritional, pernicious, hemorrhagic, hemolytic, aplastic, and sickle cell anemia.
2. Polycythemia is an abnormal increase in the number of erythrocytes.
3. Infectious mononucleosis is characterized by an elevated white cell count, especially Iymphocytes and mononucleocytes. The cause is a virus.
4. Leukemia is the uncontrolled production of white blood cells that interferes with normal clotting and vital body activities.

The Cardiovascular System - The Heart:

1. The heart is situated obliquely between the lungs in the mediastinum.
2. About two-thirds of its mass is to the left of the midline.

Parietal Pericardium (Pericardial Sac)

1. The parietal pericardium, consisting of an outer fibrous layer and an inner serous layer, encloses the heart.
2. Between the serous pericardium and the epicardium is the pericardial cavity, a space filled with pericardial fluid that prevents friction between the two membranes.

Wall – Chambers – Vessels - Valves:

1. The wall of the heart has three layers: epicardium, myocardium, and endocardium.
2. The chambers include two upper atria and two lower ventricles.
3. The blood flows through the heart from the superior and inferior venae cavae and the coronary sinus to the right atrium, through the tricuspid valve to the right ventricle, through the pulmonary trunk to the lungs, through the pulmonary veins into the left atrium, through the bicuspid valve to the left ventricle, and out through the aorta.
4. Valves prevent backflow of blood in the heart.
5. Atrioventricular (AV) valves, between the atria and their ventricles, are the tricuspid valve on the right side of the heart and the bicuspid (mitral) valve on the left.
6. The chordae tendineae and their muscles keep the flaps of the valves pointing in the direction of blood flow.
7. The two arteries that leave the heart both have a semilunar valve.

Conduction System:

1. The conduction system consists of nervous tissue specialized for impulse conduction.
2. Components of this system are the sinoatrial node (pacemaker), atrioventricular (AV) node, atrioventricular (AV) bundle, bundle branches, and Purkinje fibers.

Electrocardiogram:

1. The record of electrical changes during each cardiac cycle is referred to as an electrocardiogram (ECG).
2. A normal ECG consists of a P wave (spread of impulse from SA node over atria), QRS wave (spread of impulse through ventricles), and T wave (ventricular repolarization). The P-R interval represents the conduction time from the beginning of atrial excitation to the beginning of ventricular excitation. The S-T segment represents the time between the end of the spread of the impulse through the ventricles and repolarization of the ventricles.
3. 3. The ECG is invaluable in diagnosing abnormal cardiac rhythms and conduction patterns, detecting the presence of fetal life, determining the presence of several fetuses, and following the course of recovery from a heart attack.
4. 4. An artificial pacemaker may be used to restore an abnormal cardiac rhythm.

Blood Supply:

1. The coronary (cardiac) circulation takes oxygenated blood through the arterial system of the myocardium.
2. Deoxygenated blood returns to the right atrium via the coronary sinus.
3. Complications of this system are angina pectoris and myocardial infarction.

Cardiac Cycle:

1. Blood flows through the heart from an area of higher to lower pressure.
2. The pressure developed is related to the size and volume of a chamber.
3. A cardiac cycle consists of the systole (contraction) and diastole (relaxation) of both atria plus the systole and diastole of both ventricles followed by a short pause.
4. The movement of blood through the heart is controlled by the opening and closing of the valves and the contraction and relaxation of the myocardium.
5. With an average heartbeat of 75/min, a complete cardiac cycle requires 0.8 sec.
6. The first sound (lubb) represents the closing of the atrioventricular valves. The second sound (dupp) represents the closing of semilunar valves.
7. A peculiar sound is called a murmur.

Cardiac Output:

1. Cardiac output (CO) is the amount of blood ejected by the left ventricle into the aorta per minute. It is calculated as follows: CO = stroke volume x beats per minute.
2. Stroke volume (SV) is the amount of blood ejected by a ventricle during each systole.
3. Stroke volume (SV) depends on how much blood enters a ventricle during diastole (end-diastolic volume) and how much blood is left in a ventricle following its systole (end systolic volume).
4. The maximum percentage that cardiac output can be increased above normal is cardiac reserve.
5. Heart rate and strength of contraction may be increased by sympathetic stimulation from the cardioacceleratory center in the medulla and decreased by parasympathetic stimulation from the cardioinhibitory center in the medulla.
6. Pressoreceptors are nerve cells that respond to changes in blood pressure. They act on the cardiac centers in the medulla through three reflex pathways: carotid sinus reflex, aortic reflex, and right heart (atrial) reflex.
7. Other influences on heart rate include chemicals (epinephrine, sodium, potassium), temperature, emotion, sex (gender and physical activity), and age.

Circulatory Shock and Homeostasis:

1. Shock results when cardiac output is reduced or blood volume decreases to the point where body tissues become hypoxic.
2. Mild shock is compensated by vasoconstriction and water retention.
3. In severe shock, venous return is diminished and cardiac output decreases. The heart becomes hypoxic, prolonged vasoconstriction leads to hypoxia of other organs, and the shock cvcle is intensified.

Disorders - Homeostatic Imbalances:

1. Risk factors in heart disease include high blood cholesterol, high blood pressure, cigarette smoking, obesity, lack of exercise, diabetes mellitus, and genetic disposition.
2. The immediate causes of heart disease are inadequate coronary blood supply, anatomical disorders (patent ductus arteriosus, septal defects, valvular stenosis, and tetralogy of Fallot), and arrhythmias (heart block, flutter, fibrillation, and premature contractions).
3. Congestive heart failure (CHF) results when the heart cannot supply the oxygen demands of the body.
4. Cardiac catheterization permits physicians to determine heart disorders and pressures, to correct some defects, and to apply chemotherapy locally.
5. Hypothermia (deliberate body cooling) and the heart-lung bypass permit open-heart surgery.
   

Arteries:

1. Arteries carry blood away from the heart. Their wall consists of a tunica interna, tunica media (which maintains elasticity and contractility), and tunica externa.
2. Large arteries are referred to as elastic (conducting) arteries and medium-sized arteries are called muscular (distributing) arteries.
3. Many arteries anastomose-the distal ends of two or more vessels unite. An alternate blood route from an anastomosis is called collateral circulation. Arteries that do not anastomose are called end art.ener

Arterioles:

1. Arterioles are small arteries that deliver blood to capillaries.
2. Through constriction and dilation they assume a key role in regulating blood flow from arteries into capillaries.

Capillaries:

1. Capillaries are microscopic blood vessels through which materials are exchanged between blood and tissue cells; some capillaries are continuous, others are fenestrated.
2. Capillaries branch to form an extensive capillary network throughout the tissue. This network increases the surface area, allowing a rapid exchange of large quantities of materials.
3. Precapillary sphincters regulate blood flow through capillaries.
4. Microscopic blood vessels in the liver are called sinusoids.

Venules:

1. Venules are small vessels that continue from capillaries and merge to form veins.
2. They drain blood from capillaries into veins.

Veins:

1. Veins consist of the same three tunics as arteries, but have less elastic tissue and smooth muscle.
2. They contain valves to prevent back flow of blood.
3. Weak valves can lead to varicose veins or hemorrhoids.
4. Vascular (venous) sinuses are veins with very thin walls.

Physiology of Circulation:

Blood Flow and Blood Pressure:

1. Blood flows from regions of higher to lower pressure. The established pressure gradient is from aorta (100 mm Hg) to arteries (100-40 mm Hg) to arterioles 40-25 mm Hg) to capillaries (25-12 mm Hg) to venules (12-8 mm Hg) to veins (10-5 mm Hg) to venae cavae (2 mm Hg) to right atrium (0 mm Hg).
2. Any factor that increases cardiac output increases blood pressure.
3. As blood volume increases, blood pressure increases.
4. Peripheral resistance is determined by blood viscosity and blood vessel diameter. Increased viscosity and vasoconstriction increase peripheral resistance and thus increase blood pressure.
5. Factors that determine heart rate and force of contraction, and therefore blood pressure, are the autonomic nervous system through the cardiac center. chemicals, temperature, emotions, sex, and age.
6. Factors that regulate blood pressure by acting on blood vessels include the vasomotor center in the medulla together with pressoreceptors, chemoreceptors, and higher brain centers; chemicals; and autoregulation.
7. The movement of water and dissolved substances (except proteins) through capillaries by diffusion is dependent on hydrostatic and osmotic pressures.
8. The near equilibrium at the arterial and venous ends of a capillary by which fluids exit and enter is called Starling's law of the capillaries.
9. Blood return to the heart is maintained by several factors including increasing velocity of blood in veins, skeletal muscular contractions, valves in veins (especially in the extremities), and breathing.

Blood Reservoirs:

1. Systemic veins are collectively called blood reservoirs.
2. They store blood which through vasoconstriction can move to other parts of the body if the need arises.
3. The principal reservoirs are the veins of the abdominal organs (liver and spleen) and skin.

Checking Circulation – Pulse:

1. Pulse is the alternate expansion and elastic recoil of an artery with each heartbeat. It may be felt in any artery that lies near the surface or over a hard tissue.
2. A normal rate is between 70 and 80 beats per minute.

Measurement of Blood Pressure:

1. Blood pressure is the pressure exerted by blood on the wall of an artery when the left ventricle undergoes systole and then diastole. It is measured by the use of a sphygmomanometer.
2. Systolic blood pressure is the force of blood recorded during ventricular contraction. Diastolic blood pressure is the force of blood recorded during ventricular relaxation. The average blood pressure is 120/80 mm Hg.
3. Pulse pressure is the difference between systolic and diastolic pressure. It averages 40 mm Hg and provides information about the condition of arteries.

Circulatory Routes:

1. The largest circulatory route is the systemic circulation.
2. Two of the many subdivisions of the systemic circulation are the coronary (cardiac) circulation and the hepatic portal circulation.
3. Other routes include the cerebral, pulmonary, and fetal circulation.

Systemic Circulation:

1. The systemic circulation takes oxygenated blood from the left ventricle through the aorta to all parts of the body including lung tissue.
2. The aorta is divided into the ascending aorta, the arch of the aorta, and the descending aorta. Each section gives off arteries that branch to supply the whole body.
3. Blood is returned to the heart through the systemic veins. All the veins of the systemic circulation flow into either the superior or inferior venae cavae or the coronary sinus. They in turn empty into the right atrium.

Hepatic Portal Circulation:

1. The hepatic portal circulation collects blood from the veins of the pancreas, spleen, stomach, intestines, and gallbladder and directs it into the hepatic portal vein of the liver.
2. This circulation enables the liver to utilize nutrients and detoxify harmful substances in the blood.

Pulmonary Circulation:

1. The pulmonary circulation takes deoxygenated blood from the right ventricle to the lungs and returns oxygenated blood from the lungs to the left atrium.
2. It allows blood to be oxygenated for systemic circulation.

Fetal Circulation:

1. The fetal circulation involves the exchange of materials between fetus and mother.
2. The fetus derives its oxygen and nutrients and eliminates its carbon dioxide and wastes through the maternal blood supply by means of a structure called the placenta.
3. At birth, when lung, digestive, and liver functions are established, the special structures of fetal circulation are no longer needed.

Disorders - Homeostatic Imbalances:

1. An aneurysm is a sac formed by an outpocketing of a portion of an arterial or venous wall.
2. Coronary artery disease (CAD) refers to an inadequate blood supply to the heart muscle. Two principal causes are atherosclerosis and coronary artery spasm.
3. Atherosclerosis is a process in which fatty substances are deposited in the walls of arteries.
4. Coronary artery spasm is caused by a sudden contraction of the smooth muscle in an arterial wall that produces vasoconstriction.
5. Hypertension is high blood pressure and may damage the heart, brain, and kidneys.

The Lymphatic System:

Lymphatic Vessels:

1. The Iymphatic system consists of Iymph, Iymphatic vessels, Iymph nodes, and Iymph organs.
2. Lymphatic vessels begin as blind-ended Iymph capillaries in tissue spaces between cells.
3. Lymph capillaries merge to form larger vessels, called Iymphatics, which ultimately converge into the thoracic duct or right Iymphatic duct.
4. Lymphatics have thinner walls and more valves than veins.

Structure of Lymph Nodes:

1. Lymph nodes are oval structures located along Iymphatics.
2. Lymph enters nodes through afferent Iymphatic vessels and exits through efferent Iymphatic vessels.
3. Lymph passing through the nodes is processed by macrophages.

Lymph Circulation:

1. The passage of Iymph is from interstitial fluid, to Iymph capillaries, to Iymphatics, to Iymph trunks, to the thoracic duct or right Iymphatic trunk, to the subclavian veins.
2. Lymph flows as a result of skeletal muscle contractions and respiratory movements. It is also aided by valves in the Iymphatics.

Lymphatic Organs:

1. Tonsils are masses of Iymphoid tissue embedded in mucous membranes. They include the pharyngeal, palatine, and lingual tonsils.
2. The spleen functions as a Iymphatic organ in phagocytosis of bacteria and worn-out cells and production of Iymphocytes and plasma cells. It also acts as a reservoir for blood.
3. The thymus gland functions in immunity by processing T cells and stimulating B cells to develop into antibody-producing plasma cells.

Nonspecific Resistance to Disease:

1. The ability to ward off disease using a number of defenses is called resistance. Lack of resistance is called susceptibility.
2. Nonspecific resistance refers to a wide variety of body responses against a wide range of pathogens.
3. Nonspecific resistance includes mechanical factors (skin, mucous membranes, lacrimal apparatus, saliva, mucus, cilia, epiglottis, and flow of urine), chemical factors (gastric juice, acid pH of skin, unsaturated fatty acids, and Iysozyme), antimicrobial substances (interferon, complement. and properdin), phagocytosis, inflammation, and fever.

Immunity (Specific Resistance to Disease):

1. Specific resistance to disease involves the production of a specific Iymphocyte or antibody against a specific antigen and is called immunity.
2. Antigens are chemical substances that, when introduced into the body, stimulate the production of antibodies that react with the antigen.
3. Examples of antigens are microbes, microbial structures, pollen, incompatible blood cells, and transplants.
4. Antigens are characterized by immunogenicity, reactivity, and multivalence.
5. Antibodies are proteins produced in response to antigens.
6. Based on chemistry and structure, antibodies are distinguished into five principal classes, each with specific biological roles (IgG, IgA, IgM, IgD, and IgE).
7. Antibodies consist of heavy and light chains of amino acids and variable and constant portions.
8. Cellular immunity refers to destruction of antigens by T cells and humoral immunity refers to destruction of antigens by antibodies.
9. T cells are processed in the thymus gland; B cells may be processed in bone marrow, fetal liver and spleen, or gutassociated Iymphoid tissue.
10. T cells consist of subpopulations: killer T cells destroy antigens directly; helper T cells help B cells to produce antibodies; suppressor T cells help to regulate the immune response; and memory T cells initiate response to subsequent invasions by the antigen.
11. B cells develop into antibody-producing plasma cells under the influence of thymic hormones; memory B cells recognize the original, invading antigen.
12. The anamnestic response provides the basis for immunization against certain diseases.
13. Cancer cells contain tumor-specific antigens and are frequently destroyed by the body's immune system (immunologic surveillance); some cancer cells escape detection and destruction, a phenomenon called immunologic escape.
14. Monoclonal antibodies are pure antibodies produced by fusing a B cell with a tumor cell; they are important in diagnosis, detection of disease, treatment, preparing vaccines, and countering rejection by transplants and autoimmune diseases.

Disorders – Homeostatic Imbalances:

1. Hypenensitivity is overreactivity to an antigen. Localized anaphylactic reactions include hay fever, asthma, eczema, and hives; acute anaphylaxis is a severe reaction with systemic effects.
2. Tissue rejection of a transplanted tissue or organ involves antibody production against the proteins (antigens) in the transplant. It may be overcome with immunosuppressive drugs.
3. Autoimmune diseases result when the body does not recognize “self” antigens and produces antibodies against them. Several human autoimmune diseases are rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), rheumatic fever, hemolytic and pernicious anemias, myasthenia gravis, and multiple sclerosis (MS).
4. Acquired immune deficiency syndrome (AIDS) lowers the body’s immunity by decreasing the number of T cells and revening the ratio of helper T cells to suppressor T cells. AIDS victims frequently develop Karposi’s sarcoma and Pneumocystis carinfi pneumonia.
   

The Respiratory System:

Pulmonary Ventilation:

1. Pulmonary ventilation or breathing consists of inspiration and expiration.
2. The movement of air into and out of the lungs depends on pressure changes governed in part by Boyle's law, which states that the volume of a gas varies inversely with pressure assuming that temperature is constant.
3. Inspiration occurs when intrapulmonic pressure falls below atmospheric pressure. Contraction of the diaphragm and external intercostal muscles increases the size of the thorax, thus decreasing the intrapleural pressure so that the lungs expand. Expansion of the lungs decreases intrapulmonic pressure, so that air moves along the pressure gradient from the atmosphere into the lungs.
4. Expiration occurs when intrapulmonic pressure is higher than atmospheric pressure. Relaxation of the diaphragm and external intercostal muscles increases intrapleural pressure lung volume decreases, and intrapulmonic pressure increases so that air moves from the lungs to the atmosphere.
5. During forced inspiration, accessory muscles of inspiration (sternocleidomastoids and scalenes) are also used.
6. Forced expiration employs contraction of the internal intercostals and abdominal muscles.
7. Compliance is the ease with which the lungs and thoracic wall expand.
8. The walls of the respiratory passageways offer some resistance to breathing.
   

Modified Respiratory Movements:

1. Modified respiratory movements are used to express emotions and to clear air passageways.
2. Coughing, sneezing, sighing, yawning, sobbing, crying, laughing, and hiccuping are types of modified respiratory movements.

Pulmonary Air Volumes and Capacities:

1. Air volumes exchanged during breathing and rate of respiration are measured with a spirometer.
2. Among the pulmonary air volumes exchanged in ventilation are tidal volume, inspiratory reserve, expiratory reserve, residual volume, and minimal volumes.
3. Pulmonary lung capacities, the sum of two or more volumes, include inspiratory, functional residual, vital, and total.
4. The minute volume of respiration is the total air taken in during I minute (tidal volume times 12 respirations per minute).

Exchange of Respiratory Gases:

1. The partial pressure of a gas is the pressure exerted by that gas in a mixture of gases. It is symbolized by p.
2. Charles' law indicates that the volume of a gas is directly proportional to its absolute temperature, assuming that the pressure remains constant.
3. According to Dalton's law, each gas in a mixture of gases exerts its own pressure as if all the other gases were not present.
4. Henry's law states that the quantity of a gas that will dissolve in a liquid is proportional to the partial pressure of the gas and its solubility coefficient, when the temperature remains constant.

External Respiration - Internal Respiration:

1. In internal and external expiration 02 and CO2 move from areas of their higher partial pressure to areas of their lower partial pressure.
2. External respiration is the exchange of gases between alveoli and pulmonary blood capillaries. It is aided by a thin alveolar capillary membrane, a large alveolar surface area, and a rich blood supply.
3. Internal respiration is the exchange of gases between tissue blood capillaries and tissue cells.

Transport of Respiratory Gasses:

1. In each 100 ml of oxygenated blood, 3 percent of the 02 is dissolved in plasma and 97 percent is carried with hemoglobin as oxyhemoglobin (HbO2).
2. The association of oxygen and hemoglobin is affected by PO2, pCO2, temperature, and DPG.
3. In each 100 ml of deoxygenated blood, 7 percent of CO2 is dissolved in plasma, 23 percent combines with hemoglobin as carbaminohemoglobin, and 70 percent is converted to the bicarbonate ion.

Control of Respiration:

Nervous Control:

1. The respiratory center consists of a medullary rhythmicity area (inspiratory and expiratory area), pneumotaxic area, and apneustic area.
2. The inspiratory area has an intrinsic excitability that sets the basic rhythm of respiration.
3. The pneumotaxic and apneustic areas coordinate the transition between inspiration and expiration.
   

Regulation of Respiratory Center Activity:

1. Respirations may be modified by a number of factors, both in the brain and outside.
2. Among the modifying factors are cortical influences, the inflation reflex, chemical stimuli (02 and CO2 levels), blood pressure, temperature, pain, and irritation to the respiratory centers.

Intervention in Respiratory Crises:

1. Cardiopulmonary resuscitation (CPR) is the artificial reestablishment of respiration and circulation. The A, B, C's of CPR are Airway, Breathing, and Circulation.
2. The abdominal thrust (Heimlich) maneuver is a first aid procedure used in case of food choking. It consists of an abdominal thrust that elevates the diaphragm, compresses the lungs, and increases air pressure in the bronchial tree.

Disorders - Homeostatic Imbalances:

1. In bronchogenic carcinoma, bronchial epithelial cells are replaced by cancer cells after constant irritation has disrupted the normal growth, division, and function of the epithelial cells.
2. Nasal polyps are growths of mucous membrane in the nasal cavity.
3. Bronchial asthma occurs when spasms of smooth muscle in bronchial tubes result in partial closure of air passageways inflammation, inflated alveoli, and excess mucus production.
4. Emphysema is characterized by deterioration of alveoli leading to loss of their elasticity. Symptoms are reduced expiratory volume, inflated lungs, and enlarged chest.
5. Pneumonia is an acute inflammation or infection of alveoli.
6. Tuberculosis is an inflammation of pleura and lungs produced by the organism Mycobacterium tuberculosis.
7. Infant respiratory distress syndrome (RDS) is an infant disorder in which surfactant is lacking and alveolar ducts and alveoli have a glassy appearance.
8. Sudden infant death syndrome (SIDS) has recently been linked to laryngospasm, possibly triggered by a viral infection of the upper respiratory tract.
9. Coryza (common cold) is caused by viruses and is usually not accompanied by a fever, whereas influenza (flu) is usually accompanied by a fever.

Digestive System:

Regulation of Food Intake:

1. Food intake is regulated by two sensations: hunger and appetite.
2. The control centers for food intake (appetite center and satiety center) are located in the hvpothalamus.

Digestive Processes:

1. Food is prepared for use by cells by five basic activities: ingestion, peristalsis, mechanical and chemical digestion, absorption, and defecation.
2. Chemical digestion is a series of catabolic reactions that break down the large carbohydrate, lipid, and protein molecules of food into molecules that are usable by body cells.
3. Mechanical digestion consists of movements that aid chemical digestion.
4. Absorption is the passage of end products of digestion from the digestive tract into blood or Iymph for distribution to cells.

Organization:

1. The organs of digestion are usually divided into two main groups: those composing the gastrointestinal (GI) tract, or alimentary canal, and accessory structures.
2. The GI tract is a continuous tube running through the ventral body cavity from the mouth to the anus.
3. The accessory structures include the teeth, tongue, salivary glands, liver, gallbladder, and pancreas.
4. The basic arrangement of tissues in the alimentary canal from the inside outward is the mucosa, submucosa, muscularis, and serosa (peritoneum).
5. Extensions of the peritoneum include the mesentery, mesocolon, falciform ligament, lesser omentum, and greater omentum.

Mouth (Oral Cavity):

1. The mouth is formed by the cheeks, palates, lips, and tongue, which aid mechanical digestion.
2. The vestibule is the space between the cheeks and lips and teeth and gums.
3. The oral cavity proper extends from the vestibule to the fauces

Tongue:

1. The tongue, together with its associated muscles, forms the floor of the oral cavity. It is composed of skeletal muscle covered with mucous membrane.
2. The upper surface and sides of the tongue are covered with papillae. Some papillae contain taste buds.

Salivary Glands:

1. The major portion of saliva is secreted by the salivary glands, which lie outside the mouth and pour their contents into ducts that empty into the oral cavity.
2. There are three pairs of salivary glands: the parotid, submandibular (submaxillary), and sublingual glands.
3. Saliva lubricates food and starts the chemical digestion of carbohydrates.
4. Salivation is entirely under nervous control.

Teeth:

1. The teeth, or dentes, project into the mouth and are adapted for mechanical digestion.
2. A typical tooth consists of three principal portions: crown, root, and cervix.
3. Teeth are composed primarily of dentin covered by enamel, the hardest substance in the body.
4. There are two dentitions-deciduous and permanent.

Digestion in the Mouth:

1. Through mastication food is mixed with saliva and shaped into a bolus.
2. Salivary amylase converts polysaccharides (starches) to disaccharides (maltose).

Deglutition:

1. Deglutition or swallowing moves a bolus from the mouth to the stomach.
2. It consists of a voluntary stage, pharyngeal stage (involuntarv) and esophageal stage (involuntarv).

Esophagus:

1. The esophagus is a collapsible, muscular tube that connects the pharynx to the stomach.
2. It passes a bolus into the stomach by peristalsis.
3. It contains an upper and lower esophageal sphincter.

Stomach:

Anatomy - Histology:

1. The stomach begins at the bottom of the esophagus and ends at the pyloric sphincter.
2. Adaptations of the stomach for digestion include rugae; glands that produce mucus, hydrochloric acid, a protein-digesting enzyme, intrinsic factor, and stomach gastrin; and a three-layered muscularis for efficient mechanical movement.

Digestion in the Stomach:

1. Mechanical digestion consists of mixing waves.
2. Chemical digestion consists of the conversion of proteins into peptides by pepsin.

Regulation of Gastric Secretion:

1. Gastric secretion is regulated by nervous and hormonal mechanisms.
2. Stimulation occurs in three phases: cephalic (reflex), gastric, and intestinal.

Absorption:

1. The stomach wall is impermeable to most substances.
2. Among the substances absorbed are some water, certain electrolytes and drugs, and alcohol.

Pancreas:

1. The pancreas is connected to the duodenum via the pancreatic and accessory ducts.
2. Pancreatic juice contains enzymes that digest starch to maltose (pancreatic amylase), proteins to peptides (trypsin and chymotrypsin), terminal amino acids at the carboxyl ends of peptides (carboxypolypeptidase), neutral fats to fatty acids and monoglycerides (pancreatic lipase), and nucleotides to pentoses and nitrogen bases (nucleases).
3. Pancreatic secretion is regulated by nervous and hormonal mechanisms.

Liver:

1. Hepatic cells of the liver produce bile that is transported by a duct system to the gallbladder for storage.
2. Bile's contribution to digestion is the emulsification of neutral fats.
3. Bile secretion is regulated by nervous and hormonal mechanisms.

Gallbladder:

1. The gallbladder stores and concentrates bile.
2. Bile is ejected into the common bile duct under the influence of cholecystokinin (CCK).

Small Intestine:

Anatomy - Histology:

1. The small intestine extends from the pyloric sphincter to the ileocecal valve.
2. It is highly adapted for digestion and absorption. Its glands produce enzymes and mucus, and the microvilli, villi, and plicae circulares of its wall provide a large surface area for digestion and absorption.
3. Intestinal enzymes break down foods inside epithelial cells of the mucosa

Intestinal Digestion:

1. Intestinal enzymes break down maltose to glucose (maltase), sucrose to glucose and fructose (sucrase), lactose to glucose and galactose (lactase), terminal amino acids at the amino ends of peptides (aminopeptidase), dipeptides to amino acids (dipeptidase), and nucleotides to pentoses and nitrogen bases (nucleases).
2. Mechanical digestion in the small intestine involves segmentation and peristalsis.

Regulation of IntestinaI Secretion:

1. The most important mechanism is local reflexes.
2. Hormones also assume a role.

Absorption:

1. Absorption is the passage of the end products of digestion from the alimentary canal into the blood or Iymph.
2. Long-chain fatty acids and monoglycerides are absorbed as part of micelles, resynthesized to triglycerides, and transported as chylomicrons.
3. Chylomicrons are taken up by the lacteal of a villus.
4. The small intestine also absorbs water, electrolytes, and vitamins.

Large Intestine:

Anatomy – Histology:

1. The large intestine extends from the ileocecal valve to the anus.
2. Its subdivisions include the cecum, colon, rectum, and anal canal.
3. The mucosa contains numerous goblet cells and the muscularis consists of taeniae coli.

Digestion in the large Intestine:

1. Mechanical movements of the large intestine include haustral churning, peristalsis, and mass peristalsis.
2. The last stages of chemical digestion occur in the large intestine through bacterial, rather than enzymatic, action. Substances are further broken down and some vitamins are synthesized.

Absorption and Feces Formation:

1. The large intestine absorbs water, electrolytes, and vitamins.
2. Feces consists of water, inorganic salts, epithelial cells, bacteria, and undigested foods.

Defecation:

1. The elimination of feces from the large intestine is called defecation.
2. Defecation is a reflex action aided by voluntary contractions of the diaphragm and abdominal muscles.

Disorders - Homeostatic Imbalances:

1. Dental caries are started by acid-producing bacteria that reside in dental plaque.
2. Periodontal diseases are characterized by inflammation and degeneration of gingivae, alveolar bone, periodontal membrane, and cementum.
3. Peritonitis is inflammation of the peritoneum.
4. Peptic ulcers are craterlike lesions that develop in the mucous membrane of the alimentary canal in areas exposed to gastric juice.
5. Appendicitis is an inflammation of the vermiform appendix resulting from obstruction of the lumen of the appendix by inflammation, a foreign body, carcinoma of the cecum, stenosis, or kinking of the organ.
6. Tumors of the gastrointestinal tract may be detected by sigmoidoscopy, colonoscopy, and barium x-ray.
7. Diverticulitis is inflammation of diverticula in the colon.
8. Cirrhosis is a condition in which parenchymal cells of the liver damaged by chronic inflammation are replaced by fibrous or adipose connective tissue.
9. Hepatitis is an inflammation of the liver. Types include hepatitis A; hepatitis B; and non-A, non-B (NANB) hepatitis.
10. The fusion of individual crystals of cholesterol is the beginning of 95 percent of all gallstones. Gallstones can cause obstruction to the outflow of bile in any portion of the duct system.
11. Anorexia nervosa is a disorder characterized by a psychologically induced loss of appetite.
12. Bulimia is a binge-purge syndrome of behavior in which uncontrollable overeating is followed by forced vomiting or overdoses of laxatives.

Metabolism:

1. . Nutrients are chemical substances in food that provide energy, act as building blocks in forming new body components, or assist in the functioning of various body processes.
2. There are six major classes of nutrients: carbohydrates, lipids, proteins, minerals, vitamins, and water.
3. Metabolism refers to all chemical reactions of the body and has two phases: catabolism and anabolism.
4. Catabolism is the term for decomposition reactions that provide energy.
5. Anabolism consists of a series of synthetic reactions whereby small molecules are built up into larger ones that form the body's structural and functional components. Anabolic reactions use energy.

Carbohydrate Metabolism:

1. During digestion, polysaccharides and disaccharides are converted to monosaccharides, which are absorbed through capillaries in villi and transported to the liver via the hepatic portal vein.
2. Carbohydrate metabolism is primarily concerned with glucose metabolism.

Fate of Carbohydrates:

1. Some glucose is oxidized by cells to provide energy; it moves into cells by facilitated diffusion and becomes phosphorylated to glucose-6-phosphate; insulin stimulates glucose movement into cells.
2. Excess glucose can be stored by the liver and skeletal muscles as glycogen or converted to fat.
3. Glucose excreted in the urine can produce glycosuria.

Glucose Catabolism:

1. Glucose oxidation is also called cellular respiration.
2. The complete oxidation of glucose to C02 and H20 involves glycolysis, the Krebs cycle, and the electron transport chain.

Glycolysis:

1. Glycolysis refers to the breakdown of glucose into two molecules of pyruvic acid.
2. When oxygen is in short supply, pyruvic acid is converted to lactic acid; under aerobic conditions, pyruvic acid enters the Krebs cycle.
3. As a result of glycolysis, there is a net production of 2 molecules of ATP

Krebs Cycle:

1. Pyruvic acid is prepared for entrance into the Krebs cycle by conversion to a two-carbon compound (acetyl group) followed by the addition of coenzyme A to form acetyl coenzyme A.
2. The Krebs cycle involves decarboxylations and oxidations and reductions of various organic acids.
3. Each molecule of pyruvic acid that enters the Krebs cycle produces 3 molecules of C02, 4 molecules of NADH2, 1 molecule of FADH2, and I molecule of GTP.
4. The energy originally in glucose and then pyruvic acid is primarily in the reduced coenzymes NADH2 and FADH2.

Electron Transport Chain:

1. The electron transport chain is a series of oxidation-reduction reactions in which the energy in NADH2 and FADH2 is liberated and transferred to ATP for storage.
2. The carrier molecules involved include FAD, coenzyme Q, and cytochromes.
3. The electron transport chain yields 32 molecules of ATP and H20.

Glucose Anabolism:

1. The conversion of glucose to glycogen for storage in the liver and skeletal muscle is called glycogenesis. The process occurs in the liver and is stimulated by insulin
2. The body can store about 500 g of glycogen.
3. The conversion of glycogen back to glucose is called glycogenolysis.
4. It occurs between meals and is stimulated by glucagon and epinephrine.
5. Gluconeogenesis is the conversion of fat and protein molecules into glucose. It is stimulated by cortisol, thyroxine, epinephrine, glucagon, and growth hormone (GH).
6. Glycerol may be converted to glyceraldehyde-3-phosphate and some amino acids may be converted to pyruvic acid.

Lipid Metabolism:

1. During digestion, fats are ultimately broken down into fatty acids and monoglycerides.
2. Long-chain fatty acids and monoglycerides are carried in micelles for entrance into villi, digested to glycerol and fatty acids in epithelial cells, recombined to form triglycerides, and transported by chylomicrons through the lacteals of villi into the thoracic duct.

Fate of Lipids:

1. Some fats may be oxidized to produce ATP.
2. Some fats are stored in adipose tissue.
3. 3. Other lipids are used as structural molecules or to synthesize essential molecules. Examples include phospholipids of plasma membranes, lipoproteins that transport cholesterol, thromboplastin for blood clotting, and cholesterol used to synthesize bile salts and steroid hormones.

Fat Storage:

1. Fats are stored in adipose tissue, mostly in the subcutaneous layer.
2. Adipose cells contain lipases that catalize the deposition of fats from chylomicrons and hydrolyze fats into fatty acids and glycerol.

Lipid Catabolism:

1. Fat is released from depots and split into fatty acids and glycerol under the influence of growth hormone (GH).
2. Glycerol can be converted into glucose by conversion into glyceraldehyde-3 -phosphate.
3. In beta oxidation, carbon atoms are removed in pairs from fatty acid chains; the resulting molecules of acetyl coenzyme A enters the Krebs cycle.
4. The formation of ketone bodies by the liver is a normal phase of fatty acid catabolism, but an excess of ketone bodies, called ketosis, may cause acidosis.

Lipid Anabolism - Lipogenesis:

1. The conversion of glucose or amino acids into lipids is called lipogenesis. The process is stimulated by insulin.
2. The intermediary links in lipogenesis are glyceraldehyde-3Dhospate and acetyl coenzyme A.

Protein Metabolism:

1. During digestion, proteins are hydrolyzed into amino acids
2. Amino acids are absorbed by the capillaries of villi and enter the liver via the hepatic portal vein.

Fate of Proteins:

1. Amino acids, under the influence of growth hormone (GH) and insulin, enter body cells by active transport.
2. Inside cells, amino acids are synthesized into proteins that function as enzymes, hormones, structural elements, and so forth. Very little protein is used as a source of energy.

Protein Catabolism:

1. Before amino acids can be catabolized, they must be converted to substances that can enter the Krebs cycle; these conversions involve deamination, decarboxylation, and hydrogenation.
2. Amino acids may also be converted into glucose, fatty acids, snd ketane hadies.

Protein Anabolism:

1. Protein synthesis is stimulated by growth hormone (GH), thyroxine, and insulin.
2. The process is directed by DNA and RNA and carried out in the ribosomes of cells.

Absorptive and Postabsorptive (Fasting) States:

1. During the absorptive state, ingested nutrients enter the blood and Iymph from the GI tract.
2. During the absorptive state, most blood glucose is used by body cells for oxidation. Glucose transported to the liver is converted to glycogen or fat. Most fat is stored in adipose tissue. Amino acids in liver cells are converted to carbohydrate, fats, and proteins.
3. During the postabsorptive (fasting) state, absorption is complete and the energy needs of the body are satisfied by nutrients already present in the body.
4. The major concern of the body during the postabsorptive state is to maintain normal blood glucose level. This involves conversion of liver and skeletal muscle glycogen into glucose, conversion of glycerol into glucose, and conversion of amino acids into glucose. The body also switches from glucose oxidation to fatty acid oxidation.

Regulation of Metabolism:

1. Absorbed nutrients may be oxidized, stored, or converted, based on the needs of the body.
2. The pathway taken by a particular nutrient is enzymatically controlled and is regulated by hormones.

Minerals:

1. Minerals are inorganic substances that help regulate body processes.
2. Minerals known to perform essential functions are calcium, phosphorus, sodium, chlorine, potassium, magnesium, iron, sulfur, iodine, manganese, cobalt, copper, zinc, selenium, and chromium.

Vitamins:

1. Vitamins are organic nutrients that maintain growth and normal metabolism. Many function in enzyme systems.
2. Fat-soluble vitamins are absorbed with fats and include A, D, E, and K.
3. Water-soluble vitamins are absorbed with water and include the B vitamins and vitamin C.

Metabolism and Body Heat:

1. A Calorie is the amount of energy required to raise the temperature of 1,000 g of water 1C from 14 to 15C.
2. The Calorie is the unit of heat used to express the caloric value of foods and to measure the body’s metabolic rate.
3. The apparatus used to determine the caloric value of foods is called a calorimeter.

Production of Body Heat:

1. Most body heat is a result of oxidation of the food we eat. The rate at which this heat is produced is known as the metabolic rate.
2. Metabolic rate is affected by exercise, the nervous system, hormones, and body temperature.
3. Measurement of the metabolic rate under basal conditions is called the basal metabolic rate (BMR).

Loss of Body Heat:

1. Radiation is the transfer of heat as infrared heat rays from one object to another without physical contact.
2. Conduction is the transfer of body heat to a substance or object in contact with the body.
3. Convection is the transfer of body heat by the movement of air that has been warmed by the body.
4. Evaporation is the conversion of a liquid to a vapor.

Body Temperature Regulation:

1. A normal body temperature is maintained by a delicate balance between heat-production and heat-loss mechanisms.
2. The hypothalamic thermostat is the preoptic area.
3. Mechanisms that produce heat are vasoconstriction, sympathetic stimulation, skeletal muscle contraction, and thyroxine production.
4. Mechanisms of heat loss include vasodilation, deereased metabolic rate, decreased skeletal muscle contraction, and perspiration.

Body Temperature Abnormalities:

1. Fever is an abnormally high body temperature caused by pyrogens; stages include chill and crisis.
2. Heat cramp is painful skeletal muscle contractions due to loss of salt and water.
3. Sunstroke results in decreased blood flow to skin, reduced perspiration, and high body temperature. Fluid therapy and body cooling are indicated.
4. Heat exhaustion results in a normal or below normal body temperature, profuse perspiration, nausea, cramps, and dizziness. Rest and salt tablets are indicated

Disorders - Homeostatic Imbalances:

1. Obesity is defined as a body weight 10 to 20 percent above desirable standard as the result of excessive accumulation of fat. Causes are regulatory or metabolic.
2. Phenylketonuria (PKU) is a genetic error of metabolism characterized by an elevation of phenylalanine in the blood.
3. Cystic fibrosis is a metabolic disease of the exocrine glands in which absorption of vitamins A, D, and K and calcium is inadequate.
4. Celiac disease is a condition in which the ingestion of gluten causes morphological changes in the small intestinal mucosa resulting in malabsorption.
5. Kwashiorkor is a protein deficiency disorder characterized by hypoprotein edema, lethargy, failure to grow, and sometimes mental retardation.

Urinary System:

Urinary System:

1. The primary function of the urinary system is to regulate the concentration and volume of blood by removing and restoring selected amounts of water and solutes.
2. The filtering unit of a nephron is the endothelial-capsular membrane. It consists of the glomerular endothelium.
3. The organs of the urinary system are the kidneys, ureters, urinary bladder, and urethra.
4. The extensive flow of blood through the kidney begins in the renal artery and terminates in the renal vein.
5. The kidneys are retroperitoneal organs attached to the posterior abdominal wall.
6. Three layers of tissue surround the kidneys: renal capsule, adipose capsule, and renal fascia.
7. Internally, the kidneys consist of a cortex, medulla, pyramids, papillae, columns, calyces, and a pelvis.

Physiology:

1. The nephron is the functional unit of the kidneys.
2. Each juxtamedullary nephron consists of a glomerular capsule, glomerulus, proximal convoluted tubule, descending limb of Henle, loop of Henle, ascending limb of Henle, distal convoluted tubule.
3. The primary force behind glomerular filtration is hydrostatic pressure.
4. Filtration of blood depends on the force of glomerular blood hydrostatic pressure in relation to two opposing forces: capsular hydrostatic pressure and blood colloid osmotic pressure. This relationship is called eflfective filtration pressure (Peff).
5. If glomerular blood hydrostatic pressure falls to 50 mm Hg, renal suppression occurs because the glomerular blood hydrostatic pressure exactly equals the opposing pressures.
6. Most substances in plasma are filtered by the glomerular capsule. Normally, blood cells and most proteins are not filtered.
7. Tubular reabsorption retains substances needed by the body, including water, glucose, amino acids, and ions. The maximum of a substance that can be absorbed is called tubular maximum.
8. About 80 percent of the reabsorbed water is returned by obligatory reabsorption, the rest by facultative reabsorption.
9. Chemicals not needed by the body are discharged into the urine by tubular secretion. Included are ions, nitrogenous wastes, and certain drugs.
10. The kidneys help maintain blood pH by excreting H+ and NH4+ ions. In exchange, the kidneys conserve sodium bicarbonate.
11. The ability of the kidneys to produce either hyperosmotic or hyposmotic urine is based on the countercurrent multiplier mechanism.

Homeostasis:

1. Besides the kidneys, the lungs, integument, and alimentary canal assume excretory functions.
2. Urine volume is influenced by blood pressure, blood concentration, temperature, diuretics, and emotions.
3. The physical characteristics of urine evaluated in a urinalysis (UA) are color, odor, turbidity, pH, and specific gravity.
4. Chemically, normal urine contains about 95 percent water water and 5 percent solutes. The solutes include urea, creatinine, uric acid, hippuric acid, indican, ketone bodies, salts, and ions.
5. Abnormal constituents diagnosed through urinalysis include albumin, glucose, erythrocytes, leucocytes, ketone bodies, bilirubin, urobilinogen, casts, renal calculi, and microbes.

Ureters:

1. The ureters are partially retroperitoneal and consist of a mucosa, muscularis, and fibrous coat.
2. The ureters transport urine from the renal pelvis to the urinary bladder, primarily by peristalsis.

Urinary Bladder:

1. The urinary bladder is posterior to the symphysis pubis. Its function is to store urine prior to micturition.
2. Histologically, the urinary bladder consists of a mucosa (with rugae), a muscularis (detrusor muscle), and a serous coat.
3. A lack of control over micturition is called incontinence failure to void urine is referred to as retention.

Urethra:

1. The urethra is a tube leading from the floor of the urinary bladder to the exterior.
2. Its function is to discharge urine from the body.

Disorders - Homeostatic Imbalances:

1. Gout is a high level of uric acid in the blood.
2. Glomerulonephritis is an inflammation of the glomeruli of the kidney.
3. Pyelitis is an inflammation of the kidney pelvis and calyces; pyelonephritis is an interstitial inflammation of one or both kidneys.
4. Cystitis is an inflammation of the urinary bladder.
5. Nephrosis leads to protein in the urine due to glomerular membrane permeability.
6. Polycystic disease is an inherited kidney disease in which nephrons are deformed.
7. Filtering blood through an artificial device is called hemodialysis.
8. The kidney machine filters the blood of wastes and adds nutrients; a recent variation is called continuous ambulatory peritoneal dialysis (CAPD).

Body Fluids:

1. Body fluid is water and its dissolved substances.
2. About two-thirds of the body's fluid is located in cells and is called intracellular fluid (ICF).
3. The other third is called extracellular fluid (ECF). It includes interstitial fluid, plasma and Iymph, cerebrospinal fluid, Gl tract fluids, synovial fluid, and fluids of the eyes and ears, pleural, pericardial, and peritoneal fluids, and the glomerular filtrate.
4. Fluid balance means that the various body compartments contain the required amount of water.
5. Fluid balance and electrolyte balance are inseparable.

Water:

1. Water is the largest single constituent in the body, varying from 45 to 75 percent of body weight depending on amount of fat present and age.
2. Primary sources of fluid intake are ingested liquids and foods and water produced by catabolism.
3. Avenues of fluid output are the kidneys, skin, lungs, and GI tract.
4. The stimulus for fluid intake is dehydration resulting in thirst sensations. Under normal conditions, fluid output is adjusted by aldosterone and ADH.

Electrolytes:

1. Electrolytes are chemicals that dissolve in body fluids and dissociate into either cations (positive ions) or anions (negative ions).
2. Electrolyte concentration is expressed in milliequivalents per liter (meq/liter).
3. Electrolytes have a greater effect on osmosis than nonelectrolytes.
4. Plasma, interstitial fluid, and intracellular fluid contain varying kinds and amounts of electrolytes.
5. Electrolytes are needed for normal metabolfm, proper fluid movement between compartments, and regulation of pH.
6. Sodium is the most abundant extracellular ion. It is involved in nerve impulse transmission, muscle contraction, and fluid and electrolyte balance. Its level is controlled by aldosterone.
7. Chloride is mainly an extracellular anion. It assumes a role in regulating osmotic pressure and forming HCI. Its level is controlled indirectly by aldosterone.
8. Potassium is the most abundant cation in intracellular fluid. It is involved in maintaining fluid volume, nerve impulse conduction, muscle contraction, and regulating pH. Its level is controlled by aldosterone.
9. Calcium is principally an extracellular ion that is a structural component of bones and teeth. It also functions in blood clotting, chemical transmitter release, muscle contraction, and heartbeat. Its level is controlled by parathyroid hormone (PTH) and calcitonin (CT).
10. Phosphate is principally an intracellular ion that is a structural component of bones and teeth. It is also required for the synthesis of nucleic acids and ATP and for buffer reactions. Its level is controlled by PTH and CT.
11. Magnesium is primarily an intracellular electrolyte that activates several enzyme systems. Its level is controlled by aldosterone.

Movement of Body Fluids:

1. At the arterial end of a capillary, fluid moves from plasma into interstitial fluid. At the venous end, fluid moves in the opposite direction.
2. The state of near equilibrium at the arterial and venous ends of a capillary between filtered fluid and absorbed fluid plus that picked up by the Iymphatic system is referred to as Starling's law of the capillaries.
3. Fluid movement between interstitial and intracellular compartments depends on the movement of sodium and potassium and the secretion of aldosterone and ADH.
4. Fluid imbalance may lead to edema and overhydrahon (water intoxication).

Acid-Base Balance:

1. The overall acid-base balance of the body is maintained by controlling the H+ concentration of body fluids, especially extracellular fluid.
2. The normal pH of extracellular fluid is 7.35 to 7.45.
3. Homeostasis of pH is maintained by buffers, respirations, and kidney excretion.
4. The important buffer systems include: carbonic acid-bicarbonate, phosphate, hemoglobin-oxyhemoglobin, and protein.
5. An increase in rate of respirations, increases pH; a decrease in rate, decreases pH.

Acid Base Imbalances:

1. Acidosis is a blood pH between 7.35 and 6.80. Its principal effect is depression of the CNS.
2. Alkalosis is a blood pH between 7.45 and 8.00. Its principal effect is overexcitability of the CNS.
3. Respiratory acidosis is caused by hypoventilation; metabolic acidosis results from an abnormal increase in acid metabolic products (other than CO2) and loss of bicarbonate.
4. Respiratory alkalosis is caused by hyperventilation, metabolic alkalosis results from nonrespiratory loss of acid or excess intake of alkaline drugs.

Reproductive System:

1. Reproduction is the process by which genetic material is passed on from one generation to the next.
2. The organs of reproduction are grouped as: gonads (produce gametes), ducts (transport and store gametes), and accessory glands (produce materials that support gametes).
3. The male structures of reproduction include the testes, ductus epididymis, ductus deferens, ejaculatory duct, urethra, seminal vesicles, prostate gland, bulbourethral glands, and penis.
1. Male Reproductive System:
   1. Scrotum:
      1. The scrotum is a cutaneous outpouching of the abdomen that supports the testes.
      2. It regulates the temperature of the testes by contraction of the dartos to elevate them closer to the pelvic cavity.
   2. Testes:
      1. The testes are oval-shaped glands (gonads) in the scrotum containing seminiferous tubules, in which sperm cells are made; sustentacular cells, which nourish sperm cells; and interstitial endocrinocytes, which produce the male sex hormone testosterone.
      2. Failure of the testes to descend is called cryptorchidism.
      3. Mature spermatozoa consist of a head, midpiece, and tail. Their function is to fertilize an ovum.
      4. Spermatozoa are moved through the testes through the seminiferous tubules, straight tubules, rete testis, and efferent ducts.
      5. At puberty GnRF stimulates anterior pituitary secretion of FSH and LH. FSH initiates spermatogenesis and LH assists spermatogenesis and stimulates production of testosterone.
      6. Testosterone controls the growth, development, and maintenance of sex organs; stimulates bone growth, protein anabolism, and sperm maturation; and stimulates development of male secondary sex characteristics.
      7. Inhibin is produced by sustentacular cells. Its inhibition of FSH helps to regulate the rate of spermatogenesis.
   3. Ducts:
      1. The duct system of the testes includes the seminiferous tubules, straight tubules, and rete testis.
      2. Sperm are transported out of the testes through the efferent ducts.
      3. The ductus epididymis is lined by stereocilia and is the site of sperm maturation and storage.
      4. The ductus deferens stores sperm and propels them toward the urethra during ejaculation.
      5. Alteration of the ductus deferens to prevent fertilization is called vasectomy.
      6. The ejaculatory ducts are formed by the union of the ducts from the seminal vesicles and ductus deferens and eject spermatozoa into the prostatic urethra.
      7. 7. The male urethra is subdivided into three portions: prostatic, membranous. and spongy (cavernous).
         
      8. Accessory Glands:
      9. The seminal vesicles secrete an alkaline, viscous fluid that constitutes about 60 percent of the volume of semen and contributes to sperm viability.
      10. The prostate gland secretes an alkaline fluid that constitutes about 13 to 33 percent of the volume of semen and contributes to sperm motility.
      11. The bulbourethral glands secrete mucus for lubrication and a substance that neutralizes urine.
      12. Semen (seminal fluid) is a mixture of spermatozoa and accessory gland secretions that provide the fluid in which spermatozoa are transported, provide nutrients, and neutralize the acidity of the male urethra and female vagina.
   4. Penis:
      1. The penis is the male organ of copulation.
      2. Expansion of its blood sinuses under the influence of sexual excitation ie ealled erection
         
2. Female Reproductive System:
   1. The female organs of reproduction include the ovaries (gonads), uterine tubes, uterus, vagina, and vulva.
   2. The mammary glands are considered as part of the reproductive svstem.
   3. Ovaries:
      1. The ovaries are female gonads located in the upper pelvic cavity, on either side of the uterus.
      2. They produce ova, discharge ova (ovulation), and secrete female sex hormones (estrogens and progesterone).
   4. Uterine (Fallopian) Tubes:
      1. The uterine tubes transport ova from the ovaries to the uterus and are the normal sites of fertilization.
      2. Implantation outside the uterus (pelvic or tubular) is called an ectopic pregnancy.
   5. Uterus:
      1. The uterus is an inverted, pear-shaped organ that functions in menstruation, implantation of a fertilized ovum, development of a fetus during pregnancy, and labor.
      2. The uterus is normally held in position by a series of ligaments.
      3. Histologically, the uterus consists of an outer perimetrium, middle myometrium, and inner endometrium.
   6. Endocrine Regulations - Menstruation and Ovarian Cycles:
      1. The function of the menstrual cycle is to prepare the endometrium each month for the reception of a fertilized egg. The ovarian cycle is associated with the maturation of an ovum each month.
      2. The menstrual and ovarian cycles are controlled by GnRF, which stimulates the release of FSH and LH.
      3. FSH stimulates the initial development of ovarian follicles and secretion of estrogens by the ovaries. LH stimulates further development of ovarian follicles, ovulation, and the secretion of estrogens and progesterone by the ovaries.
      4. Estrogens stimulate the growth, development, and maintenance of female reproductive structures; stimulate the development of secondary sex characteristics; regulate fluid and electrolyte balance; and stimulate protein anabolism.
      5. Progesterone works with estrogens to prepare the endometrium for implantation and the mammary glands for milk secretion.
      6. Relaxin relaxes the symphysis pubis and helps dilate the uterine cervix to facilitate delivery.
      7. During the menstrual phase, the functionalis layer of the endometrium is shed with a discharge of blood, tissue fluid, mucus, and epithelial cells. Primary follicles develop into secondary follicles.
      8. During the preovulatory phase, endometrial repair occurs. A secondary follicle develops into a Graafian follicle. Estrogens are the dominant ovarian hormones.
      9. Ovulation is the rupture of a Graafian follicle and the release of an ovum into the pelvic cavity brought about by inhibition of FSH and release of LH.
      10. During the postovulatory phase, the endometrium thickens in anticipation of implantation. Progesterone is the dominant ovarian hormone.
      11. . If fertilization and implantation do not occur, the corpus luteum degenerates and low levels of estrogens and progesterone initiate another menstrual and ovarian cycle.
      12. If fertilization and implantation do occur, the corpus luteum is maintained by placental HCG and the corpus luteum and placenta secrete estrogens and progesterone to support pregnancy and breast development for lactation.
      13. The female climacteric is the time immediately before menopause, the cessation of the sexual cycles.
   7. Vagina:
      1. The vagina is a passageway for the menstrual flow, the receptacle for the penis during sexual intercourse, and the lower portion of the birth canal.
      2. It is capable of considerable distension to accomplish its functions.
   8. Vulva:
      1. The vulva is a collective term for the external genitals of the female.
      2. It consists of the mons veneris, labia majora, labia minora, clitoris, vestibule, vaginal and urethral orifices, and greater and lesser vestibular glands.
   9. Perineum:
      1. The perineum is a diamond-shaped area at the inferior end of the trunk between the thighs and buttocks.
      2. An incision in the perineal skin prior to delivery is called an episiotomy.
   10. Mammary Glands:
       1. The mammary glands are modified sweat glands (branched tubuloalveolar) over the pectoralis major muscles. Their function is to secrete and eject milk (lactation).
       2. Mammary gland development is dependent on estrogens and progesterone.
       3. Milk secretion is due to mainly PRL and milk ejection is stimulated by OT.

Disorders - Homeostatic Imbalances:

1. Sexually transmitted diseases (STDs) are diseases spread by sexual contact and include gonorrhea, syphilis, genital herpes, trichomoniasis, and nongonococcal urethritis (NGU).
2. Conditions that affect the prostate are prostatitis, enlarged prostate, and tumors.
3. Impotence is the inability of the male to attain or hold an erection long enough for intercourse.
4. Infertility is the inability of a male's sperm to fertilize an ovum.
5. Menstrual disorders include amenorrhea, dysmenorrhea, abnormal bleeding, and premenstrual syndrome (PMS).
6. Toxic shock syndrome (TSS) includes widespread homeostatic imbalances and is a reaction to toxins produced by Staphylococcus aureus.
7. Ovarian cysts are tumors that contain fluid.
8. Endometriosis refers to the growth of uterine tissue outside the uterus.
9. Female infertility is the inability of the female to conceive.
10. The mammary glands are susceptible to benign fibroadenomas and malignant tumors. The removal of a malignant breast, pectoral muscles, and Iymph nodes is called a radical mastectomy.
11. Cervical cancer can be diagnosed by a Pap test.
12. Pelvic inflammatory disease (PID) refers to bacterial infection of Delvic oraans.

Gamete Formation:
Diploid and Haploid Cells:

1. Ova and sperm are collectively called gametes or sex cells and are produced in gonads.
2. Uninucleated somatic cells divide by mitosis, the process in which each daughter cell receives the full complement of 23 chromosome pairs (46 chromosomes). Somatic cells are said to be diploid (2n).
3. Immature gametes divide by meiosis in which the pairs of chromosomes are split so that the mature gamete has only 23 chromosomes. It is said to be haploid (n).

Spermatogenisis:

1. Spermatogenesls occurs in the testes. It results in the formation of four haploid spermatozoa.
2. The spermatogenesis sequence consists of reduction division, equatorial division, and sperm maturation.

Oogenesis:

1. Oogenesis occurs in the ovaries. It results in the formation of a single haploid ovum.
2. The oogenesis sequence consists of reduction division, equatorial division, and ova maturation.

Sexual Intercourse:

1. The role of the male in the sex act involves erection, lubrication, and orgasm.
2. The female role also involves erection, lubrication, and orgasm (climax).

Pregnancy:

1. Pregnancy is a sequence of events that includes fertilization, implantation, embryonic growth, fetal growth, and birth.
2. Its various events are hormonally controlled.

Fertilization and Implantation:

1. Fertilization refers to the penetration of the ovum by a sperm cell and the subsequent union of the sperm and ovum nuclei to form a zygote.
2. . Penetration is facilitated by hyaluronidase and proteinases produced by sperm.
3. Normally only one sperm fertilizes an ovum.
4. Early rapid cell division of a zygote is called cleavage, and the cells produced by cleavage are called blastomeres.
5. The solid mass of cells produced by cleavage is a morula.
6. The morula develops into a blastocyst, a hollow ball of cells differentiated into a trophectoderm (future embryonic membranes) and inner cell mass (future embryo).
7. The attachment of a blastocyst to the endometrium is called implantation.
8. It occurs by enzymatic degradation of the endometrium

Embryonic Development:

1. During embryonic growth, the primary germ layers and embryonic membranes are formed and the placenta is functioning.
2. The primary germ layers-ectoderm, mesoderm, and endoderm-form all tissues of the developing organism.
3. Embryonic membranes include the yolk sac, amnion, chorion, and allantois.
4. Fetal and maternal materials are exchanged through the placenta.
5. During the fetal period, organs established by the primary germ layers grow rapidly.

Hormones of Pregnancy:

1. Pregnancy is maintained by human chorionic gonadotropin (HCG), estrogens, and progesterone.
2. Placental luteotropic releasing factor (pLRF) stimulates secretion and breast development, protein anabolism, and glucose and fatty acid catabolism.
3. Relaxin relaxes the symphysis pubis and helps dilate the uterine cervix toward the end of pregnancy.

Parturition and Labor:

1. The time an embryo or fetus is carried in the uterus is called gestation.
2. Parturition refers to birth and is accompanied by a sequence of events called labor.
3. The birth of a baby involves dilation of the cervix, expulsion of the fetus, and delivery of the placenta.

Adjustments of the Infant at Birth:

1. The fetus depends on the mother for oxygen and nutrients, removal of wastes, and protection.
2. Following birth the respiratory and cardiovascular systems undergo changes in adjusting to self-supporting postnatal life.

Potential Hazards to the Developing Embryo and Fetus:

1. The developing embryo and fetus is susceptible to many potential hazards that can be transmitted from the mother.
2. Examples are infections, microbes, chemicals and drugs, alcohol, and smoking.

Lactation:

1. Lactation refers to the secretion and ejection of milk by the mammary glands.
2. Secretion is influenced by prolaction (PRL), estrogens, and progesterone.
3. . Ejection is influenced by oxytocin (OT).
   

Birth Control:

1. Methods include removal of gonads and uterus, sterilization (vasectomy, tubal ligation, laparascopic technique), and contraception (natural, mechanical, and chemical).
2. Contraceptive pills of the combination type contain estrogens and progesterone in concentrations that decrease the secretion of FSH and LH and thereby inhibit ovulation.
   

Inheritance:

1. Inheritance is the passage of hereditary traits from one generation to another.
2. The genetic makeup of an organism is called its genotype. The traits expressed are called its phenotype.
3. Dominant genes control a particular trait; expression of recessive genes is inhibited by dominant genes.
4. Amniocentesis is the withdrawal of amniotic fluid. It can be used to diagnose inherited biochemical defects and chromosomal disorders, such as hemophilia, Tay-Sachs disease, sickle cell anemia, and Down's syndrome.
5. Down s syndrome is a chromosomal abnormality characterized by mental retardation and retarded physical development.
6. Sex is determined by the Y chromosome of the male at fertilization.