15 Chapter - Defense Mechanisms I. Nonspecific defense: barriers to penetration of body/ A. Antigens large, complex, and foreign molecules internal defenses. B. Antigenic determinant sites stimulate production of diff. A. Phagocytic cells engulf invading pathogens. antibodies. B. Interferon polypeptide secreted by infected III. Specific immunity = lymphocytes. A. B lymphocytes secrete antibodies and provide humoral cellprotect other cells immunity. II. Specific immune responses are directed against antigens. B. T lymphocytes proved cell-mediated immunity. Functions of B Lymphocytes I. five subclasses of antibodies/immunoglobulins: A. Complement fixation-proteins attach to mem.; promotes IgG/A/M/D/E cell death A. Differ in regard to polypeptides in heavy chains B. Free complement proteins promote B. Antibody has two variable regions that combine w/ opsonization/chemotaxis and stimulate release of histamine specific antigens. from tissue mast cells. C. Antibodies + antigens promotes phagocytosis. III. Specific and nonspecific immune mechanisms cooperate in the development of a local inflammation. II. Antigen-antibody complexes complement system. Active and Passive Immunity II. Passive immunity-transfer of antibodies from immune to I. Primary response first exposed to pathogen non organism A. Primary - IgM antibodies made slowly, and person likely A. Passive immunity occurs naturally in mother to fetus. to be sick B. Antiserum injections - passive to some pathogenic B. Secondary - IgG antibodies made quickly, able to resist organisms/toxins. pathogen. III. Monoclonal antibodies made by hybridomas (formed C. Active immunizations "vaccinations" artificially by fusion of B lymphs w/ multiple myeloma cells) D. Secondary bc of development of lymphocyte clones as result of antigen-stimulated proliferation of appropriate lymphocytes. Functions of T lymphocytes I. Thymus processes T lymph/secretes hormones required for F. Histocompatibility antigens (MHC molecules)- molecules effective immune response of T lymphocytes throughout on cell mem present in different combinations in different body. individuals. II. Three subcategories of T lymphocytes. III. Antigen presenting cells (macrophages/dendritic cells) A. Killer T lymph kill victim cells by w/o antibodies but partially digest foreign protein (virus)/present antigens to requires close contact bt killer T cell and victim cell. lymph on macro surface w/ class-2 MHC antigens. B. Killer T lymph responsible for transplant rejection, A. Helper T lymph require interaction w/ macrophages to be immunological defense vs fungal/viral infections, defense vs activated by foreign antigen; when activated helper T cells some bacterial infections. secrete interleukin-2. C. Helper T lymph stimulate, suppressor T lymph suppress B. Interleukin-2 stimulates killer T cells specific to foreign function of B lymph/killer T lymphocytes. antigen. D. T lymph secrete lymphokines- promote action of C. Killer T cells to attack victim cell victim cell must lymph/macrophages. present foreign antigen w/ class-1 MHC molecule. E. Receptor proteins on T lymph cell mem bind to foreign D. Interleukin-2 stimulates B lymph/secretion of antibodies antigen in combination w/ histocompatibility antigen for T IV. Tolerance to self-antigens due to destruction of lymph cell to become activated. that recognize self- antigens/suppression of immune response by suppressor T cells Tumor Immunology I. Immune surveillance vs cancer provided by killer T/natural B. Natural killer cells nonspecific, T lymphocytes specific killer cells C. Immunological surveillance vs cancer weakened by A. Cancerous cells dedifferentiate/produce fetal antigens stress. antigens presented to lymph w/ abnormal class-2 MHC antigens. Diseases Caused by the Immune System I. Autoimmune diseases caused by production of A. Immediate hypersensitivity = allergen stimulates IgE autoantibodies vs self-antigens/result from development of antibodies attach to tissue mast cells/stimulate release of autoreactive T lymphocytes. chemicals from mast cells. II. Immune complex diseases caused by inflammationfree B. Mast cells secrete histamine, leukotrienes, antigens= bound antibodies. prostaglandins, produce allergy symptoms III. Two types of allergic responses: immediate/delayed C. Delayed (contact dermatitis)- T cell-mediated response hypersensitivity Chapter 16 - The Respiratory System I. Alveoli - thin-walled air sacs that provide large sa for gas A. Structures of cavity covered by thin, wet pleural diffusion. membranes. A. Respiratory Zone - region of lungs where gas exchange B. Lungs covered by visceral pleura (normally against with the blood parietal pleura that lines chest wall) B. Conducting zone - trachea, bronchi, and bronchioles C. Intrapleural space - potential space bt visceral/parietal deliver air to ^ pleurae II. Thoracic cavity limited by chest wall and diaphragm. Physical Aspects of Ventilation
I. Intrapleural/intrapulmonary pressures vary during ventilation. A. Intrapleural pressure always less than intrapulmonary pressure. B. Intrapulmonary-<atmospheric=inspiration, >atmospheric = expiration. C. Boyle's law - inverse relationship bt volume/pressure of gas II. Mechanics of ventilation influenced by physical properties of lungs.
A. Compliance=ease of expansion- bt intrapulmonary/pleural pressure B. Elasticity= tendency to recoil after distension. C. Fluid surface tension in alveoli exerts inward force resist distension A. Collapse of alveoli bc pressure caused by surface tension > smaller alveoli than large alveoli law of La Place. B. Pulmonary surfactant (phospholipid+protein) lowers surface tension C. Hyaline mem. disease - lungs of premature collapse bc no surfactant. Mechanics of Breathing II. Spirometry aids diagnosis of pulmonary disorders. I. Inspiration/expiration contraction/relaxation of striated A. Pulmonary fibrosis - restrictive disease; vital capacity < muscles. below normal A. Quiet ins. diaphragm/external intercostal muscles B. Asthma/bronchitis - obstructive disease; forced contract increase thorax volume expiratory volume below normal bc of increased airway B. Quiet ex. muscles relax elastic recoil of resistance to air flow. lungs/thorax decrease in thoracic volume. III. Asthma bronchoconstriction; emphysema/chronic C. Forced ins/ex aided by contraction of accessory bronchitis referred to as chronic obstructive pulmonary respiratory muscles. disease. Gas Exchange in the Lungs I. Dalton's law - total pressure of gas = sum of pressures of A. [O2/CO2] dissolved in plasma = prop. to electric current each gas generated by special electrodes that react with gases. A. Partial pressure of gas in dry gas mixture = total pressure B. Normal arterial PO2 = 100 mm Hg [dissolved O2] = .3 x % comp. of gas in mixture. ml/100 ml blood; O2 in red blood cells (19.7 mL/100 ml B. Total pressure of mixture decreases with altitude above blood) does not affect PO2 sea level partial pressures of constituent gases decrease III. PO2 /PCO2 measurements of arterial blood provide info on with altitude. lung function IV. Blood flow (perfusion) in lungs must adequate/match air C. Partial pressure of wet gas mixture water vapor flow (ventilation) for adequate gas exchange to occur. pressure added II. Henry's law - amount of gas dissolved in fluid is directly V.High gas PP O2 toxicity, nitrogen narcosis, prop. to partial pressure of that gas in contact with the fluid. decompression sickness Regulation of Breathing I. Rhythmicity center in med oblongata controls muscles of B. Central chemoreceptors in med oblong sensitive to in respiration. blood PCO2 because resultant changes in pH of the cerebrospinal fluid. A. Ins/Ex neuron activity varies reciprocallyautomatic C. Peripheral chemoreceptors in aortic/carotid bodies breathing cycle sensitive to in blood PCO2 bc of changes in blood pH. B. Activity in med influenced by apneustic / pneumotaxic III. Decreases in blood PO2 stimulate breathing only when center in pons, as well as by sensory feedback information. <50 mm Hg; stimulates breathing thru chemoreceptors C. Conscious breathingcontrol by cere cortex via sensitive to in PCO2 and pH. corticospinal tracts IV. Tidal volumes of > 1 L ins inhibited by stretch II. Breathing affected by PO2, pH, PO2 of blood receptors in lungs (the Hering Breuer reflex) A similar reflex chemoreceptors may act to inhibit expiration. A. PCO2 of blood/changes in pH > blood PO2 in regulation of breathing. Hemoglobin and Oxygen Transport I. Hemoglobin-2 alpha/beta polypeptide chains + four heme B. Rise in temp decreases affinity groups w. Fe C. Affinity decrease oxy dissociation curve shift right A. Deoxyhemoglobin - Iron reduced w/o O2; (greater % unloading of oxygen to the tissues) Oxyhemoglobin = w/ O2 IV. Oxygen affinity decreased by organic molecule in rbc B. Carboxylhemoglobin Fe + CO; Methemoglobin 2,3-DPG oxidized Fe /unable to transport any gas A. Oxy inhibits 2,3-DPG production [2,3-DPG] increases C. Deoxy + O2 in lungs (loading reaction); breaks bonds in when anemia or low PO2 (as in high altitude) causes decrease tissue cap (unloading reaction) extent determined by PO2 in oxy and O2 affinity B. Anemic low [hemoglobin] partially compensated for II. Oxy dissociation curve - percent oxy saturation at diff bc ^ % oxy unload oxygen as result of 2,3-DPG. values of PO2 C. Fetal hemoglobin cannot bind to 2,3-DPG ^ O2 A. At rest, arterial/venous saturation~22% of oxy unloads affinity than mom transfer of oxygen to fetus. O2 to tissue V. Inherited amino acid defects in hemoglobin responsible for B. Exercise venous PO2 /% oxy saturation decrease ^% sickle-cell anemia and thalassemia. oxy unload VI. Striated muscles have myoglobin, related to hemoglobin, III. pH/temp influence oxygen affinity extent of loading combine with O2/deliver to muscle cell mitochondria at low and unloading. PO2 values. A. Bohr Effect - < pH decreases affinity and rise in pH increases affinity. Carbon Dioxide Transport and Acid-Base Balance I. Rbc contain carbonic anhydrasecatalyzes A. Favored by high PCO2 in tissue capillaries CO2 produced by tissue converted into carbonic acid in red blood CO2+H2Ocarbonic acid.
cells. II. Adjust [blood CO2 carbonic acid] ventilation B. Carbonic acid ionizes to form H+ and HCO3maintains proper acid-base balance of blood. (bicarbonate). A. Normal arterial blood pH is 7.40; <7.35 = acidosis, >7.45 C. H+ buffered by hemoglobin but more bicarbonate diffuse = alkalosis. outward electrical gradient established draws Cl- into B. Hyperventilationresp alkalosis; hypoventilationresp rbc chloride shift. acidosis. D. Reverse chloride shift in lungs low PCO2 favors C. Met acidosishyperventilationresp alkalosis =partial compensation conversion of carbonic acid to CO2 exhaled. Effect of Exercise and High Altitude on Respiratory Function II. Acclimatization to high altitude = help to deliver O2 I. Exercise=^ventilation (hyperpnea)^ met rate so art blood effectively to tissues, despite reduced arterial P O2. PCO2 normal A. Hyperpnea bc of proprioceptor info, cerebral input, art A. Low PO2 Hyperventilation PCO2 /pH. B. Rbc ^ 2,3-DPG v O2 affinity and improves B. Heavy exerciseanaerobic threshold reached at ~55% of unloading reaction. max O2 uptake lactic acid released into blood by muscles. C. Kidneys produce hormone erythropoietin stimulates bone marrow to ^ rbc so more oxygen can be carried by C. Endurance trainingmuscles utilize O2 more effectively blood at given values of PO2. ^ levels of exercise performed before anaerobic threshold reached. Chapter 17 Structure and Function of the Kidneys I. kidney divided into outer cortex and inner medulla. B. Glomerular blood drained by efferent arteriole - delivers A. Medulla = renal pyramids separated by renal columns. blood to peritubular capillaries surrounding nephron tubules. B. Renal pyramids empty urine into calyces that drain into C. Glomerular (Bowman's) capsule/proximal&distal tubules in cortex. renal pelvis urine flows into ureter and transported to D. Loop of Henle in medulla. bladder to be stored. II. 1 kidney = million+ func. Units- nephrons E. Distal tubule collecting ducts thru med to empty vascular/tubular comp. urine into calyce A. Filtration occurs in glomerulus - receives blood from afferent arteriole Glomerular Filtration II. GFR regulated by constriction/dilation of afferent I. Filtrate from plasma in glomerulusbasement mem of arterioles. glom cap/ thru slits in processes of podocytes (inner layer of A. Sympathetic innervation causes constriction of afferent Bowman's capsule) arterioles. A. Glomerular ultrafiltrate, formed under force of bp low B. Intrinsic mechanisms autoregulate rate of renal blood [protein] flow and GFR. B. Glomerular filtration rate (GFR) - volume of filtrate by both kidneys each minute; 115 to 125 ml/min. Reabsorption of Salt and Water I. 65% of filtered salt/water reabsorbed across proximal C. Salt transport/CCE in vasa recta tissue fluid of med= tubules. hypertonic A. Na actively transported, Cl follows passively, water D. Hypertonicity of med multiplied by positive feedback follows salt out mechanism in descending limb passively permeable to B. Salt transport in proximal tubules not under hormonal water and perhaps to salt. regulation. III. Collecting duct permeable to water but not salt. II. Countercurrent multiplier system-reabsorption of A. Collecting ducts thru hypertonic medh20 leaves by remaining water osmosis cap . A. Na actively extruded from ascending limb passively B. Permeability of collecting ducts to water stimulated by by chloride. ADH B. Ascending limb impermeable to h20remaining filtrate = hypotonic. Renal Plasma Clearance III. Almost all PAH going through kidneys cleared by I. Inulin filtered but not reabsorbed/secreted clearance = GFR filtration/secretion PAH clearance = total renal blood flow. IV. Normally all filtered glucose reabsorbed; glycosuria II. Some filtered urea reabsorbed clearance < GFR transport carriers for glucose become saturated as a result of hyperglycemia. Renal Control of Electrolyte and Acid-Base Balance IV. Nephrons filter bicarbonate/reabsorb amount required to I. Aldosterone Na reabsorption/K secretion in distal maintain acid-base balance. Reabsorption of bicarbonate is convoluted tubule. indirect. II. Aldosterone stimulated by rise in blood K/indirectly by fall in blood Na A. Filtered bicarbonate + H+ carbonic acid in filtrate. B. Carbonic anhydrase in microvilli mem in tubules catalyzes A. v blood flow thru kidneys enzyme renin secreted from carbonic acid to carbon dioxide and water. juxtaglomerular apparatus. C. CO2 reabsorbed/converted in tubule cells/rbc to carbonic B. Renin catalyzes angiotensin I formationconverted to acid dissociates to bicarbonate and H+. angiotensin II C. Angiotensin II stimulates adrenal cortex to secrete D. Nephron filter/secrete H+ excreted/buffered by aldosterone. ammonium/phosphate III. Aldosterone stimulates secretion of H+/K into filtrate for Na
Clinical Applications C. K-sparing diuretics- distal tubule inhibited to reabsorb I. Diuretic drugs increase urine volume lower blood Na+ /secrete K. volume/pressure. II. Glomerulonephritis - glomeruli leaks plasma proteins into A. Loop diuretics/thiazides inhibit active Na+ transport in the urine. ascending limb and early portion of the distal tubule III. Renal dialysis used to treat people with renal B. Osmotic diuretics - extra solutes in filtrate ^osmotic insufficiency. pressure of filtrate and inhibit osmotic reabsorption of water. Chapter 18 - Introduction to the Digestive System I. Digestion of food - hydrolysis of molecules into subunits. A. Mucosa- simple columnar epithelium, connective tissue A. Occurs in lumen of GI tract and catalyzed is by specific called lamina propria, smooth muscle called muscularis enzymes. mucosa. B. Digestion products absorbed thru intest. mucosa; enters B. Ssubmucosa - connective tissue; muscularis- smooth blood/ lymph muscles; serosa - connective tissue covered by the visceral II. Layers (tunics) of GI tract (from inside outward): mucosa, peritoneum. submucosa, muscularis, and serosa. C. Submucosa - submucosal plexus/muscularis -myenteric plexus of autonomic nerves. Esophagus and Stomach I. Peristalsis push food thru lower esophageal sphincter into B. Parietal cells of gastric gland HCl; chief cells stomach. pepsinogen II. Stomach - cardia, fundus, body, and pyloris (antrum); C. Acidic environ. pepsinogen protein- digesting pylorus w/ pyloric sphincter. enzyme (pepsin) A. Lining of stomach folds (rugae)/mucosal surface forms D. Some protein digestion in stomach; most important gastric pits gastric glands. stomach function- secretion of intrinsic factor needed for B12 absorption in intestine. Small Intestine B. Membrane of intestinal epithelial cells folded into I. Small intestineduodenum, jejunum, and ileum; common microvilli = brush border of mucosa and serves to increase bile duct/ pancreatic duct empty into duodenum. surface area. II. Villi project into lumen; at base of villi- mucosa forms III. Dig. enzymes (brush border enzymes), located in narrow pouches called crypts of Lieberkuhn. microvilli membrane A. New epithelial cells are formed in crypts. IV. Small intestine exhibits - peristalsis and segmentation. Large Intestine I. Large intestine divided into cecum, colon, rectum, and anal II. Large intestine absorbs water and electrolytes. canal. A. Most water absorbed in small intestine, but 1-1.5 L/day A. Appendix attached to inferior medial margin of the pass to large intestine absorbs about 90% of this amount. cecum. B. Na+ actively absorbed/water follows passively, ~kidneys B. Colon - ascending, transverse, descending, and sigmoid III. Anal sphincters relax/other muscles contract ^ rectal portions. pressure defecation C. Haustra - bulges in walls of the large intestine Liver, Gallbladder, and Pancreas I. Liver - largest internal organ - functional units called F. Detoxifies blood by excreting substances in bile by lobules. phagocytosis/ chemical inactivation A. Liver lobules - plates of hepatic cells separated by G. Modifies plasma concentrations of proteins, glucose, capillary sinusoids. triglycerides, and ketone bodies. B. Blood flow from periphery of each lobule (where hepatic II. Gallbladder stores/concentrates bile released thru artery/portal vein empty) thru sinusoids and out central vein. cystic/common duct to the duodenum. C. Bile flows within the hepatocyte plates, in canaliculi, to III. Pancreas - exocrine and endocrine gland. the bile ducts. A. Endocrine - islets of Langerhans secrete hormones D. Substances excreted in bile returned to liver in hepatic insulin/glucagon. portal blood; this is called enterohepatic circulation. B. Exocrine acini of pancreas make pancreatic juice E. Bile- bilirubin, bile salts, cholesterol, and other molecule (contains various digestive enzymes and bicarbonate) Neural and Endocrine Regulation of the Digestive System I. Regulation of gastric function occurs in three phases. B. Short reflexes include gastroileal reflex, ileogastric A. Cephalic phase - higher brain centers act via vagus nerve reflex, and intestino-intestinal reflexes. III. Hormones secretin and CCK regulate pancreatic stimulates gastric juice secretion. juice/bile secretion. B. Gastric phase - secretion of HCl and pepsin, controlled A. Secretin secretion by arrival of acidic chyme into by gastric contents/hormone gastrin, secreted by gastric duodenum mucosa. B. CCK secretion by presence of fat in chyme arriving in C. Intestinal phase- stomach activity inhibited by neural the duodenum. reflexes/ hormonal secretion from duodenum. C. Contraction of gallbladder in response to neural reflex II. Intestinal function regulated by local short reflexes. and to CCK secretion by duo A. Submucosal/myenteric plexuse-autonomic IV. Gastrointestinal hormones needed for maintenance of GI motor/sensory/inter-neurons tract/ accessory digestive organs. Digestion and Absorption of Carbohydrates, Lipids, and Proteins I. Starch digestion begins in mouth through salivary amylase. B. Complete digestion into monosaccharides by brush border enzymes. A. Pancreatic amylase digests starchdisaccharides/shortII. Protein digestion begins in stomach through pepsin. chain oligosaccharide
A. Pancreatic juice - protein-digesting enzymes trypsin, A. Free fatty acids/monoglycerides enter micelles (formed chymotrypsin. in bile salts)/ absorbed in this form or as free molecules. B. Brush border - digestive enzymes help complete B. Inside mucosal epi cells subunits used to resynthesize digestion of proteins triglycerides C. Amino acids, like monosaccharides, absorbed/secreted C. Triglycerides in epithelial cells + proteins into cap blood entering the portal vein. chylomicrons - secreted into the central lacteals of the villi. III. Lipids digested in small intestine after being emulsified D. Chylomicrons transported by lymph to thoracic duct and by bile salts. enter blood. Chapter 19 - Nutritional Requirements A. Metabolic rate influenced by physical activity, temp, II. Vitamins and elements serve as cofactors and coenzymes. eating; basal metabolic rate measured as rate of oxygen A. Vitamins divided into fat-soluble (A, D, E, and K) and consumption when influences standardized and minimal. water-soluble. B. Energy from food/energy consumed by body measured in B. Water-soluble vitamins needed for enzymes involved in kilocalories cell resp. C. Fat-soluble vitamins A and D have specific functions but C. Caloric intake> energy expenditure excess calories share similar mechanisms of action, activating nuclear stored as fat. receptors and regulating genetic expression. Regulation of Energy Metabolism I. Body tissues use circulating energy substrates (glucose, III. Adipose cells, or adipocytes, are targets of hormonal fatty acids, ketone bodies, lactic acid, amino acid) for cell regulation respiration. endocrine in nature. A. Different organs have different preferred energy sources. A. Children- circulating saturated fatty acids promote cell B. Circulating energy substrates obtained from food or division and differentiation of new adipocytes activity energy reserves of glycogen, fat, and protein in body involves bonding of prostaglandin, 15d-PGJ2, with nuclear II. Eating behavior is regulated by hypothalamus. receptor PPARg. A. Lesions of ventromedial area of hypo produce B. Adipocytes secrete leptin (regulates food hyperphagia; intake/metabolism) and TNFa (regulate sensitivity of skeletal lesions of lateral hypothalamus produce hypophagia. muscles to insulin) B. NT implicated in control of eating behavior (endorphins, IV. Control of energy balance in body regulated by norepi, serotonin, and cck) anabolic/catabolic effects of a variety of hormones. Energy Regulation by the Islets of Langerhans I. ^ [plasma glucose] stimulates insulin and inhibits glucagon A. Lowers [blood glucose] and ^ reserves of glycogen, fat, secretion. protein. A. Amino acids stimulate secretion of insulin and glucagon. B. Skeletal muscles - major organs removing glucose B. Insulin secretion stimulated by parasymp innervation of III. Fasting insulin secretion decreases and glucagon islets/action of intestinal hormones (gastric inhibitory peptide secretion^ (GIP)) A. Glucagon glycogenolysis in the liver, II. Intestinal absorption - insulin promotes uptake of blood gluconeogenesis, lipolysis, and ketogenesis. glucose B. Help maintain levels of blood glucose for brain/provide alternate energy sources for other organs. Diabetes Mellitus and Hypoglycemia I. Diabetes mellitus/reactive hypoglycemia represent B. Non-insulin-dependent diabetes mellitustissue disorders of islets insensitivity to insulin/inadequate insulin; aggravated by A. Insulin-dependent diabetes mellitus occurs when beta obesity/improved by exercise. cells destroyed; lack of insulin/excessive glucagon C. Reactive hypoglycemia occurs when islets secrete secretion excessive amounts of insulin in response to a rise in blood glucose concentration. Metabolic Regulation by Adrenal Hormones, Thyroxine, and Growth Hormone I. Adrenal hormones in energy regulation- epi from adrenal B. Promotes protein syn./needed for body med and glucocorticoids (hydrocortisone) from adrenal growth/development (CNS) cortex. III. Secretion of growth hormone regulated by releasing/inhibiting hormones from hypo A. Effects of epi similar to glucagon stimulates A. Stimulated by protein meal/fall in glucose (fasting) glycogenolysis/ lipolysis activates ^ metabolism of brown B. GH stimulates catabolism of lipids/inhibits glucose fat. utilization. B. Glucocort-breakdown of muscle protein/conversion of C. GH stimulates protein synthesis body growth. amine glucose in liver. D. Anabolic effects (bone growth in childhood) produced II. Thyroxine stimulates rate of cell resp in almost all cells in indirectly via polypeptides called insulin-like growth factors, the body. or somatomedins. A. Thyroxine sets basal metabolic rate (BMR) (rate at which energy (and oxygen) consumed by body under resting conditions) Regulation of Calcium and Phosphate Balance II. PTH - bone resorption/calcium reabsorption in kidneys I. Bone Ca/phosphate in hydroxyapatite crystals reserve supply raises [Ca] A. Formation/reabsorption of bone by A. Secretion of PTH stimulated by fall in blood calcium osteoblasts/osteoclasts, respectivel levels. B. [plasma Ca/phosphate] affected by intestinal B. PTH inhibits reabsorption of phosphate in kidneys absorption/urinary excretion of these ions. more is excreted
III. 1,25-dihydroxyvitamin D3 derived from vitamin D by hydroxylation. A. Last hydroxylation step is stimulated by PTH B. 1,25-dihydroxyvitamin D3 stimulates intestinal absorption of calcium and phosphate, resorption of bone, and renal reabsorption of phosphate.
IV. ^ PTH ^ 1,25-dihydroxyvitamin D3 production maintain proper blood levels of Ca/phosphate in response to a fall in calcium levels. V. Calcitonin secreted by parafollicular cells of thyroid gland. A. Secretion stimulated by rise in blood calcium levels. B. Calcitonin lowers blood calcium by inhibiting bone resorption and stimulating the urinary excretion of calcium and phosphate. Chapter 20 - Sexual Reproduction B. Testes of male embryo secrete testosterone/mllerian A. Female accessory sex organs- uterus and uterine (fallopian) tubes. inhibitory factor. MIF no female acces. sex B. Testosterone (via conversion to dihydrotestosterone) organs/testosteronemale acces. sex organs. promotes formation of male external genitalia; female II. Male accessory sex organs - epididymis, ductus (vas) genitalia formed when absent. deferens, seminal vesicles, prostate, and ejaculatory duct. Endocrine Regulation of Reproduction I. Gonads stimulated by ant pit hormones: FSH and LH II. ^ FSH /LH secretion at puberty due to maturational changes in brain and v sensitivity of hypo/pit gland to A. Secretion stimulated by GnRH hypothalamus. negative feedback effects B. FSH/LH secretion under control of gonads by negative feedback exerted by gonadal steroid hormones and by a III. Pineal gland secretes melatonin inhibitory effect on peptide called inhibin. gonadal function in some mammals, but role in human physiology controversial. Male Reproductive System I. LH secretion- negative feedback from testos, FSH III. Diploid spermatogonia in sem tubules meiosis inhibin from testes haploid sperm. A. Testosterone conversion to 5a-reduced A. Four spermatids formed develop into spermatozoa by androgen/estradiol. maturational process called spermiogenesis. B. Secretion relatively constant and does not decline sharply B. Sertoli cells in seminiferous tubules required for II. Testosterone promotes growth of soft tissue/bones before spermatogenesis. epiphyseal discs have sealed = anabolic steroids. C. Puberty testos needed for meiosis/FSH A. Secreted by interstitial cells of Leydig under stimulation spermiogenesis. of LH. IV. Spermatozoa in semin tubulesepididymisdrained B. LH receptor proteins located in interstitial tissue. FSH from epididymis into ductus deferens; prostate and seminal receptors in Sertoli cells in seminiferous tubules. vesicles add fluid to the semen. C. Leydig/Sertoli cells secrete autocrine regulatory V. Penile erection produced by parasymp-induced molecules interact vasodilation. Ejaculation produced by symp stimulation of peristaltic contractions Female Reproductive System I. Human sexual response excitation, orgasm, plateau, and A. Ovulation secondary oocyte extruded from ovary resolution. does not complete second meiotic division unless fertilized. II. Primordial follicles in ovary have primary oocytes B. After ovulation - empty follicle endocrine gland (arrested at prophase of first meiotic division) corpus luteum. A. Small # of oocytes stimulated to complete first meiotic C. Ovarian follicles secrete only estradiol, division 2 Corpus luteum secretes both estradiol and progesterone. B. Secondary oocyte- complete cell formed other IV. Hypo secretes GnRH in pulsatile fashion pulsatile product- polar body secretion of gonadotropins needed to prevent III. One of secondary follicles grows large graafian follicle desensitization ovulated. Menstrual Cycle I. Follicular phase, ovarian follicles stimulated by FSH from E. Progesterone/estradiol secretion ^ during luteal phase; (-) ant pit feedback on FSH and LH secretion. A. Follicles grow, mature, and secrete increasing amounts of F. No continued stimulation by LH corpus luteum estradiol. regresses at end of luteal phase estradiol/progesterone B. Day 13 rapid ^ in estradiol LH surge from ant pit declines menstruation/new cycle (+) feedback II. ^ [estradiol] during follicular phase proliferative phase C. LH surge stimulates ovulation at about day 14. of endometrium; progesterone secretion during luteal D. After ovulation, LH stimulation corpus luteum phase secretory luteal phase III. Oral contraceptive pills contain estrogen/progesterone negative feedback control of FSH and LH secretion. Fertilization, Pregnancy, and Parturition B. O2, nutrients, wastes exchanged by diffusion bt I. Sperm acrosomal reaction penetrate corona fetal/maternal blood. radiata/zona pellucida. III. Placenta secretes hCS, hCG and steroid hormones. A. Fertilizationsecondary oocyte completes meiosis A. hCS similar to prolactin/GH; hCG similar to LH/TSH. second polar body B. Major steroid hormones secreted by placenta - estriol. B. Diploid zygote undergoes cleavage to form a morula Placenta/fetal glands cooperate in production of steroid blastocyst. Implantation of blastocyst in endometrium begins hormones. bt fifth and seventh day. IV. Contraction of uterus in labor stimulated by oxytocin II. Trophoblast cells of blastocyst secrete hCG (~LH); from post pit/ prostaglandins, produced within the uterus. maintains corpus luteum for the first 10 weeks of pregnancy.
A. Androgens, primarily DHEA, secreted by fetal adrenal cortex converted to estrogen by placenta. B. Estrogen from the placenta induces oxytocin; enhances uterine sensitivity/promotes prostaglandin synthesis in uterus labor/delivery. V. High levels of estrogen during pregnancy stimulate growth and development of mammary glands.
A. Prolactin (prolactin-like hCS) stimulate milk protein production Prolactin secretion/action blocked during pregnancy by ^ estrogen B. After delivery, estrogen levels fall, prolactin milk production. C. Milk-ejection reflex- neuroendocrine reflex - stimulus of suckling reflex secretion of oxytocin ejection of milk from the nipple.