Biology 2222 Course Content Outline

I. HOMEOSTASIS AND CAPILLARY HEMODYNAMICS

    A. Extracellular and Intracellular Fluid Compartments of the Body

    B. Interstitial Fluid Environment of Body Cells

        1. Nutrient reservoir and waste depository functions of fluid environment

        2. Unicellular vs. multicellular life forms (similarities and differences)

    C. Capillary Origin and Reclamation (Circulation) of Interstitial Fluid

        1. Primary outward force = Hydrostatic Blood Pressure

        2. Primary inward force = Plasma Osmotic (oncotic) Pressure and Albumin

II. CARDIOVASCULAR PHYSIOLOGY

    A. Blood as a Tissue - Cells and Matrix Components

        1. Blood plasma

            a. Straw colored fluid matrix of blood

            b. Transport vehicle for dissolved nutrients, wastes, and heat energy

        2. Cellular Components (Formed Elements) of blood

            a. Erythrocytes (Red Blood Cells)

                1. Respiratory pigment (hemoglobin) for oxygen transport

                2. Oxygen saturation curve and dynamics

                3. Erythrocyte production and component recycling

                    a. Reticuloendothelial organ (spleen) removal of old RBC's

                    b. Iron recycling and liver storage

                    c. Erythropoietin and marrow production (erythropoiesis)

            b. Leukocytes (White Blood Cells) and Defensive Functions

                1. Differential and Total White Cell Counts

                2. Polymorphonuclear Granulocytes

                    a. Neutrophil - phagocytes capable of diapedesis

                    b. Eosinophil - function unclear; associated with allergies and intestinal parasites

                    c. Basophil - heparin and histamine storage and release

                3. Mononuclear Agranulocytes

                    a. Monocyte - large, phagocytic white cell with differentiation capability

                    b. Lymphocyte - cellular and humoral immunity

                        1. True immunity vs. innate resistance

                        2. Immunity = antigen-antibody interactions

                        3. B-cell lymphocytes and humoral immunity (plasma cells and immunoglobulin, Ig, production)

                4. T-cell lymphocytes and cellular immunity

                    a. Regulator T-cells (CD4 and CD8)

                    b. Effector T-cells (Tctl, cytotoxic T's)

                5. Types of Acquired Immunity

                    a. Passive Immunity - transfer of antibody to confer temporary protection

                    b. Active Immunity - exposure to antigen to stimulate permanent antibody production

                        1. Active Natural - immunity resulting from contracting a disease

                        2. Active Artificial - Immunity resulting from immunization injections

    B. The Heart (Structure/Function Relationships)

        1. Cardiac Muscle Specializations - Anatomical and Physiological Syncytium

        2. Cardiac Anatomy

            a. Chambers (atria and ventricles) and valves (Atrioventricular and Semilunar)

            b. Great vessels (systemic and pulmonary arteries and veins)

        3. Conductile System of the Heart

            a. Nodal Tissue Specializations

                1. Sinoatrial Node (pacemaker)

                2. Atrioventricular Node (A-V delay for phase synchronization)

            b. Conductile Tissue Specializations

                1. Purkinje Fibers

                2. Bundle of His with right and left bundle branches

        4. Cardiac Cycle, Valve Function, and Directional Blood Flow

            a. Diastasis (A-V's open, semilunars closed)

            b. Atrial excitation and the S-A node (A-V's open, semilunars closed)

            c. Atrial contraction/systole (A-V's open, semilunars closed)

            d. Ventricular contraction/systole with atrial relaxation/diastole

                1. Isovolumic Phase - all valves closed; ventricular pressures increasing to diastolic levels; first heart sound

                2. Ejection Phase - A-V's closed, semilunars open; stroke volume ejected into arteries

            e. Ventricular relaxation/diastole (A-V's open, semilunars close, second heart sound)

            f. Return to Diastasis (A-V's open, semilunars closed)

        5. Cardiac Cycle and the Simple Electrocardiogram

            a. P-wave = atrial excitation/depolarization

            b. P-R interval = delay across the A-V node

            c. QRS complex = ventricular excitation/depolarization

            d. T-wave = ventricular recovery/repolarization

    C. Blood Vessel Structure/Function Relationships

        1. Vessel Tissue Layers

            a. Tunica Intima

            b. Tunica Media

            c. Tunica Adventitia

        2. Arteries - thick walled, high pressure vessels

            a. Conducting - Tunica media rich in connective tissue for elastic recoil

            b. Distributing - Tunica media rich in smooth muscle for constriction/dilation

            c. Arteriole - Vasomotor control of blood flow in capillary beds; point of greatest resistance in peripheral circulation.

        3. Veins - thin walled, low pressure vessels

            a. Differentiated by caliber or diameter

            b. Different from arteries by thinner Tunica Media layer of smooth muscle

        4. Arteriosclerosis vs. Atherosclerosis

    D. Establishment and Maintenance of Hydrostatic Blood Pressure

        1. Hydrostatic pressure is directly related to blood volumethe - greater the volume in a given vessel, the greater the pressure.

        2. Volume, and therefore pressure, in a given vessel is equal to the amount put into the vessel (controlled by cardiac output)
                related to the amount drained out (controlled by peripheral resistance).

        3. Thus, Blood Pressure = Cardiac Output X Peripheral Resistance

            a. Factors affecting cardiac output (volume pumped/unit time (about 5L /minute)

                1. Cardiac output = Stroke Volume (ejection volume) X Rate (beats per minute)

                    a. Factors affecting stroke volume (Stroke Vol. = EDV - ESV)

                        1. EDV = Full volume at the end of diastole controlled by venous return (passive venous pump;
                            venous valves; gravity)

                        2. ESV = Residual volume left in ventricle at the end of systole controlled by strength of contraction
                            (strength-tension curve and Frank-Starling Law of Muscle).

                    b. Factors affecting heart rate

                        1. Baroreceptor reflex

                        2. Chemoreceptor reflex

            b. Factors affecting peripheral resistance and laminar flow

                1. Vessel length

                2. Vessel diameter (vasoconstriction vs. vasodilation)

                3. Turbulence in path of blood flow

                4. Blood viscosity and hematocrit

    E. Lymph and Lymphatic Circulation

        1. Lymphatic capillary valves and interstitial fluid pressure activation

        2. Lymph nodes and lymph circulation

III. RESPIRATORY SYSTEM PHYSIOLOGY

    A. Gas Exchange and Fick's Law of Diffusion

        1. Lung surface area and diffusion rate; pulmonary surfactant

        2. Distance, alveolar wall thickness, and diffusion rate

        3. Concentration gradients and diffusion rate

    B. Upper Respiratory Structures and Functions

        1. Nasal Cavities

            a. Conchae and Vibrissae - warming, moistening and filtering air

            b. Vomer and nasal septum

        2. Pharyngeal Divisions

            a. Nasopharynx

            b. Oropharynx

            c. Laryngopharynx

    C. Larynx and Phonation

        1. Laryngeal cartilages

        2. Vocal cords

    D. The Bronchial Tree and Airway Branching (Conducting vs. Respiratory)

        1. Conducting Airways (Airflow via pressure gradients; no gas exchange)

            a. Levels of branching in conducting airways correlate with lung anatomy

            b. Terminal bronchioles and airflow reduction

                1. Leukocytes and particle removal

                2. Alpha-1-Antitrypsin (AAT) and emphysema

            c. Conducting Airway Ventilation and Negative Pressure Breathing

                1. Intrapulmonary Space - airflow by positive and negative pressure changes

                2. Intrapleural Space - continual negative pressure and lung inflation

                3. Lung Volumes and Capacities

                    a. Tidal Volume

                    b. Residual Volume and Functional Residual Volume

                    c. Inspiratory Reserve

                    d. Expiratory Reserve

                    e. Vital Capacity

                    f. Total Lung Capacity

                4. Conducting Airways and Dead-Space Air

            d. Respiratory Arways

                1. Alveoli and gas exchange

                2. Alveolar ventilation

    E. Minute Volume and the V/Q Ratio

        1. Because of conducting airway "dead space" air,of the 500 ml Tidal volume, only about 300 ml is "fresh"air.

        2. Assuming an average of 16 (12 to 20) breaths per minute, about 4,800 ml (approximately 5 liters) of fresh
             air enters the lungs each minute.

            a. This volume of fresh air per minute is termed the Minute Volume

            b. Minute Volume is the ventilation (V) numerator of the V/Q ratio

        3. The demoninator, (Q) represents the blood flow through the lungs per minute and is termed Perfusion.

            a. Assuming a normal cardiac output volume of blood is passed through the lungs each minute (about 5 liters),
                then perfusion would be about 5 liters

            b. Thus, in a normal individual, the V/Q ratio (5/5) would approach 1.

        4. V/Q ratios below 1 represent states of hypoventilation because air ventilation volume would be less than blood perfusion

        5. Similarly, V/Q ratios above 1 represent hyperventilation because air ventilation volume would be more than blood perfusion

IV. RENAL PHYSIOLOGY

    A. The kidneys and associated structures selectively remove wastes from circulating blood, and help control blood volume
        and pressure by excreting or retaining water and solutes.

        1. A "waste" is anything in excess in circulating blood

            a. "Nitrogenous Wastes" are organic molecules (urea and uric acid) resulting from protein and nucleic acid
                metabolism in the liver.

            b. Anything else in excess, such as water and electrolytes, are also selectively removed

        2. Thus, excess water and solutes, can be removed or retained by the kidneys (urine formation) to control
             blood volume and blood pressure.

    B. Kidney Gross Anatomy and Histology

        1. Proper urine formation requires bringing blood close to a large surface, the glomerular membrane, for processing.

        2. Each kidney contains about one million functional Nephron units, each with a glomerular membrane surface

        3. Each nephron glomerular membrane consists of the glomerular capillary walls and the inner wall of the
            renal capsule (Bowmans capsule).

        4. Fluids crossing this surface by filtration pass into the Proximal Convoluted Tubule (PCT).

        5. The PCT leads to a long looping tubule section, the Loop of Henle.

        6. The Loop of Henle leads to a Distal Convoluted Tubule (DCT) which, along with other nephron units, empties
            into a Collecting Duct.

        7. Collecting ducts comprise the Pyramids of the renal medulla and empty into calyces of the the renal pelvis,
            which is the flared beginning of the ureter

        8. Ureters, one from each kidney, enter the urinary bladder from below and behind for storage until voiding via the
            Micturition Reflex which contracts bladder muscle while relaxing sphincter muscles leading to the urethra and
            outside the body

    C. Processes of Urine Formation

        1. Glomerular Filtration

            a. Blood passes through glomerular capillaries under pressure and, as in systemic capillaries, plasma and small solutes
                leak across the glomerular membrane into the capsule cavity.

            b. Blood cells and high molecular weight albumin protein are normally too large to filter into the capsule.

            c. Everything else, including nitrogenous wastes, essential water, nutrients, and electrolytes, can pass across the
                glomerular membrane and could potentially be lost from the body.

        2. Tubular Reabsorption

             a. Active and passive transport mechanisms relating to the Tmax return essential materials from the glomerular filtrate
                back into circulating blood across the remaining nephron tubule walls to prevent loss with the urine.

            b. By definition, wastes are not reabsorbed and are lost with the urine.

            c. Most water, nutrients and anions are reabsorbed across the PCT wall while cations are reabsorbed primarily
                across the DCT.

            d. All reabsorbed materials can return to circulating blood via the Vasa Recta capillaries which surround the
                nephron tubules.

        3. Tubular Secretion

            a. Cells of the PCT can also actively transport materials in reverse, from blood into the nephron tubule,
                to assist in waste removal

            b. Tubular secretion increases the blood cleansing efficiency of the nephron

    D. Regulation of Urine Formation and Kidney Function

        1. Intrinsic (within the kidney itself) and the Juxtaglomerular Apparatus

            a. Afferent and efferent arterioles "straddle" the macula densa portion of the DCT, which monitors fluid flow
                through each nephron unit.

            b. When systemic blood pressure is low, glomerular filtration drops off and the macula densa detects a slowed fluid flow.

            c. Macular cells stimulate Juxtaglomerular cells of the afferent artierole to release an enzyme, renin.

            d. Renin converts a plasma precursor protein (angiotensinogen) into angiotensin-I

            e. Capillary beds, primarily of the lungs and kidney, contain an enzyme, angiotensin converting enzyme (ACE),
                which converts angiotensin-I into angiotensin-II.

            f. Angiotensin-II is a powerful vasoconstrictor which constricts the efferent arteriole to reduce blood drainage from
                the glomerulus raising glomerular blood pressure and restoring filtration levels toward normal.

            g. Angiotensin-II also causes systemic vasoconstriction raising systemic blood pressure to further increase
                glomerular filtration.

            h. Aldosterone from the adrenal cortex is also released to cause fluid retention across nephron tubules further
                increasing blood pressure.

        2. Extrinsic Mechanisms

            a. Antidiuretic Hormone (ADH), the countercurrent multiplier system and osmoregulation by the kidney

                1. When solutes in circulating blood become too concentrated raising the osmotic pressure, osmoreceptors of the
                   hypothalamus are stimulated.

                2. Osmoreceptors stimulate cells of the hypothalamus to release via the posterior pituitary gland a hormone, ADH.

                3. ADH travels via blood to the DCT cells of the kidney where it causes increased water pore formation increasing
                    the permeability of these cells to water.

                4. With the countercurrent multiplier system keeping the sodium levels high outside DCT cells, water moves easily
                    through the increased pores to concentrate the urine and return water to circulating blood.

                5. As water returns to circulating blood, blood osmotic pressure drops and ADH secretion is diminished.

                6. This mechanism allows kidney regulation of blood volume and osmotic pressure.

            b. Aldosterone

                1. Aldosterone is a steroid hormone from the adrenal cortex which is released when blood potassium levels are too high.

                2. Aldosterone acts on nephrons to stimulate secretion of potassium into the urine for excretion.

                3. However, potassium and sodium transport are linked via "pump" mechanisms and loss of potassium is accompanied
                    by sodium and water retention.

                4. Thus, aldosterone causes blood volume and pressure to increase by fluid retention.

V. GASTROINTESTINAL PHYSIOLOGY

    A. Gross Anatomy and Histology

        1. "Tube-within-a-tube" body plan with the GI tract forming the inner tube (approx. 21 ft in length).

        2. Entire GI tract lined with epithelium, with types being specialized for function

            a. High friction areas, such as oral cavity, esophagus and rectum, have non-keratinized stratified squamous.

            b. Secretory or absorptive areas, such as stomach and intestine, have simple columnar with microvilli to
                increase absorptive surface in small intestine.

        3. Wall of entire GI tract possesses two smooth muscle layers, one arranged circularly and another longitudinally,
            to produce segmental and peristaltic contractions for material mixing or movement respectively.

    B. Processes of Digestion-serve to reduce food material to a molecular size that is absorbable across cell membrane surfaces and
            eventually into circulating blood. NOTE! Technically food and secretions of the GI tract are not truly inside body until
            a cell membrane surface has been crossed.

        1. Mechanical Degradation

            a. Mechanical disruption of food material forming small particles.

            b. Increases surface area to aid enzymatic breakdown.

        2. Liquification

            a. Secretions of specialized glandular structures, such as saliva from salivary glands and pepsin-HCl from gastric glands.

            b. Liquefied food material keeps food molecules in solution to enhance chemical reactions breaking them into
                absorbable sizes.

        3. Enzymatic hydrolysis

            a. Nutrient energy rich foods consist of macromolecular (polymers) carbohydrates, proteins, lipids, and nucleic acids, all
                comprised small molecular subunits (monomers) joined chemically by dehydration synthesis.

            b. Enzymes specific for each macromolecular type catalyze reactions that break polymers into absorbable monomers
                by returning the water molecules removed by dehydration synthesis.

        4. Absorption

            a. Membrane transport mechanisms of cells lining the small and large intestine absorb molecular monomers
                resulting from hydrolysis.

            b. Cells then pass materials into circulating blood for distribution and/or storage.

        5. Digestive tract can be divided into specialized areas that participate in one or more of the digestive processes,
            a regionally specialized gut tube.

    C. Oral (buccal) Cavity

        1. Mouth opening leads into oral cavity which contains teeth (heterodont dentition) and a muscular tongue and
            cheek pouches.

        2. Three pairs of accessory salivary glands empty amylase-rich saliva into oral cavity via salivary ducts to begin
            starch hydrolysis.

        3. Region specialized for liquefaction, mechanical degradation (mastication/chewing) with no nutritionally important
            absorption occurring here.

    D. Oropharynx

        1. Begins anatomically with the palatine arches and leads to the laryngopharynx and esophagus.

        2. Possesses sensory receptors which, when stimulated, initiate involuntary phase of swallowing (deglutition).

        3. Specialized for food transport with no nutritionally important absorption occurring.

    E. Esophagus

        1. Muscular tube lined with squamous epithelium and containing smooth muscle in its wall.

        2. Capable of peristalsis to move material from pharynx to stomach across glottis closed by epiglottis.

        3. No nutritionally important absorption occurring here.

    F. Stomach

        1. Muscular organ specialized for storage and early food processing and consisting of a cardiac, fundus,
            body, and pyloric antrum regions.

        2. Site of beginning protein hydrolysis via gastric gland secretions.

            a. Parietal Cells - secrete HCl, for a final pH approaching 1.5.

            b. Chief Cells - secrete pepsin, a protease working best at acid pHs.

        3. Some mechanical degradation via stomach contractions.

        4. No nutritionally important absorption.

    G. Small Intestine - distal to the pyloric sphincter of stomach; longest region of GI tract.

        1. Duodenum - First several inches of the small intestine

            a. Receives alkaline and enzyme-rich secretions of the pancreas to neutralize stomach acid and to complete hydrolysis
                of all macromolecular food types.

            b. Receives bile secretions from the liver/gall bladder to emulsify water insoluble lipids and speed their hydrolysis.

        2. Jejunum - middle length of small intestine specialized for mixing and absorption.

        3. Ileum - terminal length of small intestine joining large intestine at cecum via ileocecal valve.

        4. Small intestine is major site of nutrient absorption in the GI tract and has extensive surface area.

            a. Length of small intestine adds absorptive surface.

            b. Villi, the finger-like projections of the mucous membrane, add surface area.

            c. Microvilli (brush border) on mucous membrane epithelial cells further add to absorptive surface.

        5. Most nutritionally important hydrolysis and absorption occurs in the small intestine.

        6. Nutrients absorbed into Hepatic Portal System and transported directly to liver.

            a. Each villus contains an arteriole, a venule and a lacteal lymph vessel.

            b. Carbohydrate and protein hydrolysis products absorbed into blood vessels of villi.

            c. Lipid hydrolysis products reconstructed in epithelial cells and passed into lymph for return directly to circulating blood.
                Lipids combined with proteins to make them soluble in blood plasma and form lipoproteins (HDLs, LDLs, etc.).

    H. Large Intestine (Colon)

        1. Specialized for feces formation by removing excess water from undigested residues.

        2. Some vitamin absorption as well.

        3. Sigmoid colon and rectum collect wastes until defecation; vascularized rectum continues water absorption until elimination.

    I. Control of Gastrointestinal Activity to Conserve Energy

        1. Salivary glands and saliva secretion

            a. Sympathetic stimulation - produces mucus-rich saliva with little enzyme content or activity.

            b. Parasympathetic stimulation - produces watery, enzyme-rich secretion aiding starch hydrolysis, but only minimally.

            c. Anticipation of a meal increases activity via neural mechanisms which are enhanced by presence of material in
                oral cavity.

        2. Swallowing (Deglutition) Reflex

            a. Voluntary Phase - moving food bolus into oropharynx

            b. Involuntary Phase - stimulation of receptors in oropharynx starts contractions in pharynx and esophagus
                to complete swallowing.

        3. Gastric Secretion (neural and hormonal controls)

            a. Neural Control (cephalic phase of gastric control) - anticipation of a meal increases gastric motility and secretions.

            b. Hormonal Control (gastric phase gastric control) - presence of material in stomach stimulates endocrine secretion of
                "gastrin" which travels via blood back to stomach to increase activity.

        4. Increased gastric activity moves material into duodenum where distension increases peristaltic and segmental
            contractions of small intestine

            a. GIP from intestinal mucosa slows stomach activity hormonally.

            b. CCK from intestinal mucosa stimulates gall bladder contraction and bile ejection.

            c. Secretin from intestinal mucosa stimulates pancreatic secretions and ejection.

        5. Increased movement of small intestine increases material entering colon.

            a. Haustra of colon slow movement to aid in final water absorption.

            b. Gastrocolic and duodenocolic reflexes compact undigested residues in sigmoid colon and rectum.

        6. Distension of rectum initiates defecation reflex causing increased colon peristalsis and relaxation of internal anal sphincter
            (involuntary smooth muscle), the defecation reflex.

        7. Voluntary relaxation of external anal sphincter (voluntary striated muscle) allows expulsion of undigested wastes.

VI. BASAL METABOLISM

    A. Monomeric subunits of carbohydrates, lipids and proteins are used by cells of the body for the energy required
        to produce ATP.

    B. Nutrient sources are prioritized as to their use: Carbohydrates (60% of diet) are top priority and stores in the body are
        turned over rapidly; Lipids (20-30% of diet) are second priority and are used when energy requirements exceed food intake;
        Proteins (20-30% of diet) are lowest priority and do not turn over rapidly.

    C. The liver is a major metabolic organ that stores and processes nutrients absorbed across the intestinal mucosa releasing them
        as blood levels drop.

        1. Metabolic Pool Concept - Nutrients in blood and interstitial fluid that can be used by cells for metabolic energy are
            collectively termed the "metabolic pool" of the body.

        2. Absorptive Phase Metabolism - Replenishing the metabolic pool with nutrients absorbed across the digestive tract
            after eating.

        3. Postabsorptive Phase Metabolism - Replenishing the metabolic pool with nutrients mobilized from stores in liver and
           other body cells during the period between meals.

        4. Hormonal Control of Metabolism Phases

            a. Insulin - from the endocrine islets of the pancreas is released when blood sugar (glucose) is high as after eating.
                Insulin assists cells with the uptake of glucose to bring blood sugar levels down and increase storage
                (liver glycogenesis).

            b. Glucagon - antagonizes insulin to raise blood sugar when levels are low by mobilizing stored reserves
                between meals (liver glycogenolysis).

        5. Abnormalities of Pancreatic Control

            a. Hypoglycemia

            b. Hyperglycemia and diabetes

        6. Thyroid Control of and Measurement of Basal Metabolism

            a. Thyroid hormone activity assays

            b. Calorimetry measurements

        7. Respiratory Quotient (RQ) and Assessing Nutritional Status

VII. TEMPERATURE CONTROL

    A. Hypothalamic "thermostat" and Homeothermy

        1. Normally set to keep core temperature at 37C or 98.6F

        2. Maintains normal temperature by activating either heat loss mechanisms or heat production/conservation
            mechanisms as needed.

        3. Temperature regulation is always a balance between heat loss and heat prod./conservation activities.

    B. Heat Loss Mechanisms Utilize Body Surfaces Exposed to Outside Air (eg.-skin and lung surfaces).

        1. Radiation - Infrared heat loss from body surface.

        2. Conduction - Transfer of heat from warm to colder bodies.

        3. Convection -Warmer molecules carried away from body surface and replaced by colder ones.

        4. Evaporation - Warmer molecules of liquid escape as vapor leaving colder ones.

        5. Vasodilation - Blood vessels to surfaces dilate carrying more warm blood (radiator effect).

    C. Heat Production/Conservation Mechanisms

        1. Metabolic Inefficiency - Cellular metabolism releases energy as heat.

            a. Metabolic energy production occurs constantly regardless of environmental temperatures.

            b. Thyroid activity can increase metabolic heat production only with prolonged exposure to cold or
                abnormal hyperthyroidism.

        2. Vasoconstriction - Blood vessels to skin surface can constrict to reduce heat loss.

        3. Piloarection - Elevation of hair shafts generates dead air space next to skin; not effective in human because of
                body hair texture.

        4. Clothing - Additional clothing substitutes for fine hair texture.

        5. Shivering - Inefficient muscle contractions used to generate heat.

    D. When Environmental Temperatures Exceed Normal Body Temperatures

        1. Only evaporative heat loss is effective.

        2. Other heat loss mechanisms can actually serve as heat "gains" under these conditions.

    E. Fever

        1. Products from damaged tissues as with inflammation can cause resetting of hypothalamic thermostat to higher set point.

        2. Higher hypothalamic set point activates heat producing/conserving mechanisms causing symptoms of fever.

VIII. REPRODUCTIVE ENDOCRINOLOGY

    A. Functions of Gonadal Tissue Same in Both Sexes

        1. Gamete production through meiotic cell divisions.

        2. Sex Steroid production characteristic of sex:

            a. Female sex hormones - Estrogens (estradiol and progesterone).

            b. Male sex hormones - Androgens (testosterone).

    B. Gonadal Tissue Controlled by Anterior Pituitary Gonadotrophins in Both Sexes

        1. Follicle Stimulating Hormone(FSH) - controls gamete production in both sexes.

        2. Luteinizing Hormone - controls sex hormone production in both sexes.

    C. Female Menstrual Cycle

        1. Cyclically repeating events (28 day average cycle) result from anterior pituitary inhibition by estrogens from the ovary.

        2. Cyclical events occur in anterior pituitary, ovary, and uterine endometrial lining.

        3. Follicular Phase of Menstrual Cycle

            a. Anterior pituitary releases FSH since estrogen inhibition is absent.

            b. FSH stimulates follicle development in ovary.

            c. Developing follicle thecal cells secrete primarily estradiol.

            b. Estradiol blocks FSH production (negative feedback) and stimulates growth of uterine endometrium.

            c. Estradiol may stimulate pituitary release of LH, causing ovulation via rupture of vesicular (Graafian) follicle.

        4. Ovulatory Phase of Menstrual Cycle

            a. Begins with LH induced ovulation.

            b. LH also causes remaining cells of ovarian follicle to become a corpus luteum releasing progesterone and
                beginning the postovulatory phase of the menstrual cycle.

        5. Postovulatory (Luteal) Phase of Menstrual Cycle

            a. Progesterone from the corpus luteum prevents uterine endometrium from sloughing.

            b. Corpus luteum persists for 6-8 days allowing enough time for a fertilized ovum to reach uterus.

            c. Involution of corpus luteum yields a corpus albicans (scar tissue) and estradiol and progesterone levels
                in blood fall dramatically.

            d. Without ovarian hormones, uterine endometrium breaks down beginning menstrual flow, the pituitary resumes
                FSH release, and the cycle repeats.

    D. HCG and Modifications of Pregnancy.

        1. HCG and Protection of Uterine Endometrium.

        2. The placenta as a temporary endocrine gland.

    E. Male Reproductive Endocrinology

        1. Seminiferous tubules of testicles produce spermatozoa via meiotic divisions of cuboidal cells in tubule walls
            under FSH stimulation.

        2. Interstitial Cells (of Leydig) secrete androgens under LH stimulation.

        3. Anterior pituitary is not inhibited in male so gonadal functions occur continuously without cyclic interruption.

    F. Menopause and Male Climacteric

        1. Physiological changes.

        2. Psychosocial involvement.

    G. Physiology of Contraception

        1. Barrier Methods (condom, diaphragm, and IUD??)

        2. Chemical Methods (spermacides)

        3. Hormonal Methods (birth control pills and implants)

        3. Surgical Methods (tubal ligation and vasectomy)

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