Test 3 Study Guide
Test 3 Study Guide BSC 116
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This 18 page Study Guide was uploaded by Rani Vance on Monday November 2, 2015. The Study Guide belongs to BSC 116 at University of Alabama - Tuscaloosa taught by a professor in Fall 2015. Since its upload, it has received 17 views. For similar materials see Principles Biology II in Biological Sciences at University of Alabama - Tuscaloosa.
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Date Created: 11/02/15
BSC 116 Test 3 Study Guide ****MUST KNOW DIAGRAMS FOR CIRCULATORY SYSTEM (INCLUDING HEART), DIGESTIVE SYSTEM, REPRODUCTIVE. Processes: 11 Steps in flow of blood thru both circuits understand antigen receptors and how they differ in terms of acquired and innate immunity osmolarity excretion secretion (endocrine system) asexual and sexual reproduction, know the differences between the two as well as the benefits less focus on lecture 31 understand general concepts Hormones and their functions Pituitary Gland Hormones: Hormone: Function: Adrenocorticotropic hormone (ACTH) Stimulates adrenal cortex Folliclestimulating hormone (FSH) Stimulates estrogen secretion, ovum production, and sperm production Growth hormone (GH) or somatotropic Regulates the growth of body tissue, hormone (STH) mainly in muscles and bones Lactogenic hormone Stimulates breast development and milk production Luteinizing hormone (LH) Stimulates ovulation and testosterone production Melanocytestimulating hormone (MSH) Controls pigmentation of skin cells Thyroidstimulating hormone (TSH) Stimulates the hormone gland Antidiuretic hormone (ADH) Regulates urine secretion Oxytocin Stimulates uterine contractions and release of breast milk Nonsteroid hormones of the Adrenal Medulla Epinephrine or adrenaline: increases heart rate; dilates the bronchioles; raises blood glucose level Norepinephrine or noradrenaline: causes the blood vessels to constrict and thereby raises the blood pressure 10/12 Lecture 2324 Circulation and Gas Exchange circulatory systems: facilitate exchange with the environment ALL cells need to be capable of exchange with their environment all reactions in cells depend on resources moving in, waste products moving out all cells must have access to this single celled/ simple multicelled contact with medium diffusion distances are short large multicelled: some/most cells isolated from external environment circulatory systems vary in complexity gastrovascular cavities lack specialized circulatory tissue Specialized because low surface area/ volume ratio Three Basics: 1. circulatory fluid: carries resources/waste 2. interconnecting tubes thru which fluid travels 3. heart muscular pump Open Circulatory System anthropods: most mollusks circulatory fluid, hemolymph direct contact with organs, have same interstitial fluid advantage: lower pressures, fluid as hydrostatic skeleton, body movements help circulate Closed Circulatory System Annelids, cephalopods, vertebrates *circulatory fluid separate from interstial fluid higher pressure in closed system metabolically expensive, provides oxygen and nutrients Cardiovascular System atrium receives blood ventricle pumps away arteries carry blood from heart arterioles: small vessels that carry blood to the capillaries, where exchange takes place capillary bed= nutrient/gas exchange network capillaries converge into venules, converge into veins carry blood back to the heart arteries and vein distinguished by the DIRECTION of blood flow Single Circulation: In fish 2 chambered hearts blood passes thru 2 capillary beds during circuit runs at lower pressure Double circulation Tetrapod with 3 or 4 chambered hearts blood pumps thru 2 separate circuits right side= pulmonary circuit to lungs, oxygen poor blood to lungs left side= systemic circuit to body, maintains higher pressure/velocity of blood 11 Steps in flow of blood thru both circuits 1. right ventricle, pumps blood to lungs 2. via pulmonary artery 3. blood flows thru capillary bed for left and right lungs 4. blood returns left atrium with pulmonary veins 5. left ventricle pumps out to the rest of the body 6. via the aorta, including coronary arteries to the heart 7. one branch leads to capillary beds in head/ arms 8. another branch leads to capillary beds in abdomen/ legs 9. deoxygenated blood drains from head/ arms via superior vena cava 10. deoxygenated blood drains from legs/ abdomen via inferior vena cava 11. both empty to right atrium right ventricle Cardiac cycle alternates pumping and filling cardiac cycle: complex sequence of pumping (systole) and filling (diastole) heart rate: 70 mL per ventricle in single contraction cardiac output 5L/min (per ventricle) (increases with activity) (striated and involuntary muscle) 4 valves keep blood from flowing in the wrong direction one way flaps, bigger than the opening they cover atrioventricular valve (AV) between chambers semilunar between ventricle/arteries heart murmurs defective valve leads to back flow Pacemaker: auto rhythmic cells of heart; contraction based upon own electrical impulses begins at sinoatrial node: cause atria to contract, empty into ventricles replayed atrioventricular node offer is delayed, ventricles contract nervous system can speed up/ slow down rate with activity level Structure of blood vessels change with their function all vessels, capillaries, arteries, and veins have an open lumen lined endothelium capillaries: smallest, just larger than blood cells thin walls to facilitate diffusion: endothelium/basal lamina arteries: layer of smooth muscle, then layer of elastic connective tissue thicker veins muscle can contract to control flow connective tissue can recoil during diastole to keep up pressure veins: layer of smooth muscle 10/14 Lecture 2324 continued The structure of blood vessels changes with their function **pressure highest in the heart and lowest in the capillary Both velocity and pressure drops as blood moves through the capillary bed **one way valves keep blood moving forward is due to SURFACE AREA arteries branch, total crosssection area increases; velocity of blood decreases through capillaries slow velocity facilitates efficient diffusion speeds up again as capillaries coalesce into veins pressure highest during ventricular systole stretches arteries; heart beats again before pressure completely dissipated vasconstriction/vasodilation can change pressure: during activity, stress, and thermoregulation Capillaries are sites of exchange between blood and tissue only a small fraction of capillaries have blood flowing thru at all times, diverted to where it is needed head, heart, kidneys usually running at capacity blood to skin used to control temperature blood to digestive tract with meals blood to the muscles during exercise Exchange occurs by both pressure & diffusion oxygen and CO e2changed by diffusion (NO ATP REQUIRED) water moves by pressure blood pressure forces water out at arterial end osmotic pressure draws water back at venous end 85% water recovered by capillaries: rest returned via lymphatic system network of small vessels that drain excess interstitial fluid: lymph eventually returned to circulatory system moves by smooth muscle contraction, aided by skeletal muscle with series of valves 15% of water goes to lymph and is recovered later in the body Blood composed of various cells and proteins in a liquid matrix open circulatory (hemolymph) continuous with interstitial fluid closedblood more comples connective tissue: cell and cell fragments (plasmas) plasma90% water, with dissolved salts, proteins, lipid, clotting/gases and waste Cellular Components erythrocytes: red blood cells, 5 trillion per 1L leukocytes: white blood cells platelets cell fragments involved in clotting Clotting: damage plugged with platelets/ fibrin protein Multipotent stem cells located in bone marrow: procedure new blood cells lymphoid: differentiate B cells and T cells myloid: differentiate 5 type white blood cells or red blood cells Gas Exchange occurs across respiratory surfaces Gas has pressures rather than concentrations partial pressure of O 2is the fraction of total pressure exerted by air O 21% by volume 2 pressure of CO =20.29 mm Hg partial pressure of dissolved gas equals partial pressure in the air, but concentration depends on temperature, salinity gas diffuses high pressure to low pressure O 2more available than water 21% of air, easier to move around 40 x less O 2 same volume water; warmer, saltier holds less All O 2must be exchanged through water: cell membranes need moist membrane entirely by diffusion; rate proportional to surface area, inversely proportional Aquatic organisms have more efficient gas exchange surfaces less O available, so less wasted 2 various respiratory surfaces among invertebrates fish have gills; delicate out foldings of body surface surface area much greater than that of the body counter current exchange of respiratory medium maintained by ventilation more surface through medium capillaries flow in the opposite direction PO i2 blood always less than in medium very efficient: removes 80% of dissolved O 2 won’t work on land Two common terrestrial adaptations for breathing air most common tracheal system series of air tubes that branch throughout the body gas exchange does not involve circulatory system Most familiar: lungs; vertebrates large infoldings of the body subdivided to increase surface area air in thru nostrils; filtered and warm to larynx via pharynx; held open by cartilage, opens to trachea trachea branches into two bronchibronchioles surface covered by cilia Ventilation of exchange surfaces achieved by breathing Amphibians: positive pressure breathing push air in by shrinking oral cavity Mammals: negative pressure breathing pull air in by expanding thoracic cavity with muscles and diaphragm controlled by breathing control centers in brain by negative feedback (CO 2 determined by pH) (coordinated with circulatory system) birds are more efficient and complex use posterior and anterior air sacs to regulate oneway & low air, no mixing of old and new Hemoglobin is necessary because O has low solubility in water 2 during exercise, you need 2 L O pe2 minutes under normal conditions, 1 L of water has 0.045 L O 2 O 2transported attached to respiratory pigment; hemoglobin reduces necessary cardiac output to 12.5 L per minute in erythrocytes 4 protein subunits, each with Fe atom, reversibly binds O 2 subunits cooperative: affinity varies as P O va2 es Bohr shift 10/16 Immune systems are necessary for multicellular animals internal environment for pathogens: foreign invaders that try to coopt organismal resources, cause disease Among vertebrates, there are two levels of immunity 1. Innate active all the time (not dependent on infection) found in all animals inhibit, detect broad range of pathogens invertebrate only line of defense **1 line of defense is the skin, 2 is phagocytosis 2. Acquired adapted immunity: response enhanced by previous infection, highly specific only vertebrates have this Innate immunity proved general protection from pathogens Invertebrates, eg insects barrier= waxy chitin low pH and lysozom: digest bacteria cell walls of microbes Hemocytes in hemolymph: phagocytosis and various chemical protections ID tags fungi unique cell wall with polysaccharides bacteria cell wall contains polymer with sugar and amino acids Antimicrobial peptides: disrupt pathogen plasma membranes of fungi and bacteria elicit specific chemical responses Vertebrates st 1 barrier= skin, mucus coverings over exchange surfaces lysosome in saliva, mucus, tears sweat lowers skin pH; low stomach pH 2 barrier= tolllike receptor (TLR) that recognize pathogen bits ID “bits” as noncell activation triggers innate immune response Phagocytic cells= engult and digest microbes; 4 types 1. neutrophils= circulate in blood 2. microphages= circulate around the body 3. demdritic= found on skin 4. eosinophils= mucus surface Antimicrobial Proteins interferins: produced by cells infected with viruses, signal other cells to produce anti viral compounds complement system: proteins in blood plasma activated by lyseinflammation **lymph nodes filled with microphages Lymphatic system: organs to trap foreign particles (tonsils, spleen, appendix) Inflammatory response and actions of natural kill cells inflammatory response: release of signaling molecules following infection/injury most cells release histamine, a signaling molecule, vessels dilate, become permeable activate macrophages also release signaling molecules, cytokines, promote blood flow blood to site= warmth, swelling: antimicrobial proteins, formation of pus (concentration of white blood cells) Systemic (vs local) inflammatory responses increase production of white blood cells (=macrophages and lymphocytes) fever: accelerate repair, kill invaders natural killer cells: can recognize and chemically destroy diseased cells normal body cells produce class 1 MHC surface proteins infected or cancerous do not NK cells look for such cells and kill them Vertebrates: Acquired immunity involves immunological memory same white blood cells (lymphocytes) have an enhanced response to infections the body has previously encountered immunological memory two lymphocytes originate from stem cells in bone marrow B cells: mature in bone marrow T cells: mature in thymus Each lymphocyte has receptors for only a single foreign molecule, an antigen lymphocytes activated by binding to specific antigens displayed on cell surfaces, using antigen receptors B cells secrete antigen receptors that bind to foreign molecules some T cells detect and kill infected cells ********Need to know how antigens function Antigens: typically proteins or polysaccharides (surface of pathogen) T&B lymphocytes have antigen receptors in plasma membrane (100,000 per cell, differ in morphology across B and T cells) exact same binding sites Epitope small part of antigen that is recognized and bound to antigen reception **ALL antigen receptors on a single lymphocyte are the same 1= a lymphocyte B cell antigen receptors and antibodies some B lymphocytes produce antigen receptors= antibodies (immunoglobulin) Week of Notes 10/1910/23 10/19 Antigen receptors composed ob variable and constant regions B cell receptor: Y shaped; 4 polypeptides 2 identical heavy chains & 2 identical light chains heavy chains linked by sulfide bonds heavy chains transmembrane each chain has constant (c) and variable (v) regions c transmembrane with sulfide bonds v at tips: form 2 asymmetrical antigen binding sites antibodies (immunoglobulin) similar: no transmembrane region soluble T cell receptor: a and b linked by sulfide bonds c and v regions, but with 1 antigen binding site Antigen recognition by a T cell, only bind to “presented” antigens antigen is free broken off with an epitope Lymphocyte diversity arises from genomic shuffling followed by filtering right chain: composed of three regions (variable, joining, constant) each with multiple options: 40 V x 5J x 1C= 200 recombinase= enzyme randomly linked to a V and a J all subsequent daughter cells identical genome changed DNA deleted between randomly selected V and J segments heavy chain: similar, but with even more options lymphocytes tested for selfreactivity: inactivated or destroyed, for selftolerance Infection leads to selection for activation of specific antigen receptors with so many random antigen receptors, unlikely that all will be specific for particular epitopes activated lymphocytes amplified by clonal selection Activated B or T cells divide many times Primary immune response: first response production of effectors (plasma cells) peaks 1017 days production of memory cells lead to immunological memory Secondary immune response: second exposure peaks faster 27 days and higher two kinds of cells: cytotoxic T cells and helper T cells Helper T cell initiate that humoral and cell mediated immune response 2 kinds of T cells: enhance humoral and cell mediated responses binds to antigen presenting macrophage, dendritic cell, or B cell, class II MHC, TCR, and accessory proteins cells exchange signaling molecules (cytokines) stimulates B cells humoral response 1 and to cytotoxic and cells (cellmediated response). humoral immune response activation and clonal selection of effector B cells “antibody medicated response” secrete antibodies that circulate in blood and lymph cellmediated =effecter T cells activated by binding class I MHC, TCR, and accessory proteins, secrete proteins MHC proteins on surface of cells present antigens to T cells genes of major histocompatibility complex make proteins that present Humoral Response helper T cells 1 mediator T cells activated by antigen piece present activation of B cells requires interaction will antigens presenting cells activated helper T cells, activates B cell presenting matching antigen antibodies interfere with pathogen function Neutralization: bind to virus, bacterium or toxin Oposonization: binding sites for macrophages Other ways to get antibodies besides active immunity from infections Vaccinations= immunization: introduction of antigens to immunity passive immunization: antibodies from mother to fetus through milk lasts only for a few weeks or a month artificial passive immunization: inject antibodies directly eg. Snake (antivenom) 10/21 Osmoregulation, excretion and endocrine systems are linked life arose in marine environment; many taxa still strictly marine concentration of boy fluids similar to surrounding environment no specializations for osmoregulation toxic waste products of metabolism terrestrial environment complicates issue further must retain water in a dry environment Osmoregulation maintaining concentration of solutes in body fluids move solutes and water will follow water uptake is not equal to water loss. Burst/dry up Osmosis: water moves from low solute high solute across a permeable membrane osmolarity: measure of osmic pressure mOs M/L eg. Blood 300mOs M/L; sea water is 1000 mOs M/L sea water is hyperosmotic to blood (hypoosmotic) osmoregulator: body fluid regulated many marine invertebrates osmoconformers freshwater/ terrestrial and some marine species most organisms tolerate a wide range (euryhaline) Vertebrates tend to be osmoregulators marine cod: osmolarity of body fluids lower than sea water (hypo osmotic) water loss to environment (osmosis) drink lots of sea water Cl ions actively excreted from gills and kidneys eg fresh water perch: osmolarity of body fluids > than fresh water (hyper osmotic) water gained by osmosis from environment excretion of water from gills lose salts by diffusion active ions take up from food and kidneys eg. terrestrial human: dehydration is a problem adaptations to retain water: mostly watertight lose water thru urine, feces, sweating replaced by drinking water Habitat and phylogeny influence nitrogenous waste protein/nucleic acid metabolism results in ammonia NH 3 highly toxic but highly soluble terrestrial organisms must retain water Many vertebrates convert ammonia urea by adding CO lower t2xicity (can be concentrated to conserve water) Reptiles and birds produce uric acid less toxic nonsoluble precipitates as a solid but uric acid is costly to produce ATP Trade off: terrestrial turtles uric acid vs. aquatic urea/ammonia Most excretory systems tubular theme control osmolarity of hemolymph/ blood to control osmolarity of body fluid generally a transport epithelium: some surface specialized to more solutes/water into/out of in general urine produced through a 4 step process: 1. filtration: body fluid forced thru semipermeable membrane 2. reabsorption: water and ions taken back in 3. secretion: wastes actively added to filtrate 4. excretion: remaining filtrate urine leaves body. Excretory System among invertebrates: Protonephridia of flatworms: beating cilia inside flame bulb draw body fluid into tubules, filtrates, excreted metanephridia: beating cilia draw body fluid in the tubes reabsorption in with capillaries in both osmoregulation re excretion malpighian tubules of insects: immersed with hemolymph solutes secreted by transport epithelium from hemplymph Mammalian kidney Solutes from blood outside each kidney served by renal artery and renal vein: lots of blood, 25% of what leaves the heart goes here fluid leaves each kidney via ureter each ureter drains to common urinary bladder drains to outside via urethra: controlled by sphincter muscles renal cortex and inner renal medulla; lots of blood vessels and excretory tubules nephron: functional kidney long tubule; beings with Bowman’s capsule (cluster of capillaries) Path of filtration with in nephron: Bowman’s capsule proximal tubule loop of Henle; mammals extends into renal medulla distal tubule, then to common collecting duct collecting ducts join to form renal pelvis drains to ureter. 10/26 Kidney function depends upon an osmolarity gradient and selective reabsoption filtration begins as blood pressure forces fluid into Bowman’s capsule from glomerulus proximal tubule: first stage of concentration active reabsorption of Na Cl follows in interstitial fluid by osmosis also K, nutrients etc movement of ions draws out water as well wastes retained in filtration; some drugs/ toxins actively secreted Descending loop of Henle; reabsorbtion of water permeable to water but not salts osmolarity gradient from cortex to inner medulla draws water across transport equilibrium further concentration of filtrate ascending loop of Henle: reabsorption of NaCl ATP IS NECESSARY FOR ALL OF THESE PROCESSES Volume & Osmolarity high/low water intake: make concentrated urine; low salt/ high water intake: make dilute urine high as 1200 mOs M/L: 4x that of body fluids as low as 70 mOs M/L Antidiurectic hormone: released in response to high blood osmolarity made in hypothalamus, stored in pituitary targets distal tissue and collecting ducts: increases water permeability, concentrates urine hormone RAAS (renninangiotensinaldosteronesystem) maintains blood pressure when BP low it initiates enzyme cascade resulting in arterial construction ** nephron highly regulates: constantly changing in order to maintain osmoregularity Hormones control more than osmoregularity involved in growth/ development involved in 1 of 4 basic systems for regulation endocrine signaling: hormones circulate in blood/hemolymph &activate target cells paracrine/ autocrine signaling: secrete molecules “local regulators,” that act over short distances, reach target cells by diffusion synaptic and neuroendocrine: network of neurons transmit chemical signals (neurotransmitters) to other cells across synaptic/ neurohormones diffuse from nerve cell endings into bloodstream pheromones: chemicals released outside body to affect another organism (for warning or to attract a mate) Three types of hormones: 1. polypeptides: proteins water soluble 2. steroid: lipids and cholesterol; lipid soluble 3. amines: from tyrosine Water soluble cell membrane receptors initiate signal transduction and response binds to receptor initiate signal transduction Lipid soluble: move across cell membrane, receptors within cell/ nucleus receptor hormone complex Receptor locality and response pathways water soluble membrane receptors initiate cell hormones circulate widely, but only affect target cells with receptors epinephrine in liver and blood vessels (skeletal/intestinal) Various stimuli lead to secretions from endocrine cells act on various target cells with specific receptors response leads to reduction in stimulus thus, negative feedback occurs Glucose level insulin and glucagon maintain blood glucose at 90 mg/100 mL both hormones produced in pancreas increased blood glucose leads to release of insulintarget almost all cells (not brain) to take up glucose, liver converts blood glucose Diabetes Type 1: autoimmune disorder that kills cells that make insulin Type 2: occurs over time Notes for 10/26 and 10/28 In general, the endocrine and nervous system act in coordination Signals from the nervous system initiate and maintain hormonal signaling vertebrate hypothalamus: endocrine gland in brain, important for nervous/endocrine coordination brain gets input from all over the body, hypothalamus reacts neurosecretory signals from hypothalamus travel to the pituitary stores 2 hormones from hypothalamus antidiuretic hormone regulates blood osmolarity oxytocin stimulates milk production; released by suckling (positive feedback) anterior pituitary: makes several hormones that are released upon stimulation from hypothalamus wide variety of targets some tropic hormones: those that regulate other endocrine glands Hormones respond to a wide variety of stimuli, including stress Also involved in stress behavior: adrenal glands (on top of kidney) short term: fight or flight response long term: stressed for the entire semester, affecting different aspects of you health adrenal cortex (outer) adrenal medulla (neural tissue) stress leads to release of 2 amines adrenal medulla: epinephrine and nepinephrine prepare body for short term excitement Short term stress response: 1. glycogen broken down to glucose 2. increased blood pressure 3. increased breathing rate 4. increased metabolic rate adrenal cortex long term stress (mineral ocorticoids) 1. retain sodium/water 2. decrease blood volume Vertebrate not really representation of animal reproductive modes Sexual reproduction: fusion of haploid (n) gametes (sperm and egg) to form diploid (2n) zygote Asexual gonochoristic: separate male and female internal fertilization gametes mingle in female’s tract external ie frogs in water asexual: new individuals with out sex (ie meiosis=cloning) fission: one splits off into 2 budding: one grows off another fragmentation: breakage, followed by regeneration parthenogenesis: offspring develop from fertilized eggs Why isn’t asexual reproduction more popular? represents a paradox if each female produces two offspring, then a population w/o sex doubles every generation population with males constant asexual should quickly replace sexual population but…. THERE IS NO VARIATION if there was an environmental change, the whole population would be wiped out because they do not have the ability to adapt alteration of asexual and sexual is a more stable solution In many taxa, it is an advantage not to have separate sexes sex of an individual is determined by gonads male testes produce sperm females ovaries produce eggs vertebrates tend to be ghonochoristic External fertilization (can occur in an aquatic environment) spawning: both sperm and egg are released in water some synchronize based on environmental cues some individual species interact more (courtship and mating rituals) Internal fertilization necessary in terrestrial habitats many lack specialized organs ie spiders pass sperm bundles by legs, and insert sperm into themselves Female reproduction is costly and highly regulated Productions of gametes (gametogenesis) lots of energy > sperm spermatogenesis of sperm simple; lots at 1 time, sperm relatively small DNA Spermatogenesis from oogenesis in 3 ways 1. # of gametes formed by meiosis a. all four products become gametes b. oogenesis only a single meiotic egg produced 2. timing of meiotic divisions a. spermatogenesis occurs continuously throughout b. oogenesis much of process completed before birth 3. pace of meiotic division a. spermatogenesis sperm produced continuously throughout b. oogenesis there are long pauses during development Male Penis urethra and erectile tissue scrotum contains testes (spermatogenesis) Internal sex organs testes: composed of highly controlled somniferous tubules, produce sperm leydig cells testosterone epididymis: highly controlled tubes: sperm take 3 weeks to mature ejaculation: process of getting sperm outside form epididymis to muscular vas deferens ejaculatory duct opens to urethra sperm mixed with products of 3 glands to make 25 mL of semen 70130 million sperm per mL seminal vesticles Spermatogenesis: lots of sperm at one time spermatogonium: diploid (2n) stem cells, w/testes primary spermatocyte: 2n secondary spermatocytes: n x 2 (products of meiosis I) spermatids: n x 4 (products of meiosis II) sperm cell: n x 4 mature in seminiferous tubule become motile in epididymus, ejaculation ***must know circulatory, digestive diagrams; be able to label 10/28 Gametogenesis in both male and female are under hormonal control hormones come from hypothalamus, anterior pituitary, and the gonads themselves GnRH from hypothalamus, stimulates anterior pituitary gland to secrete FSH& LH FSH & LH from pituitary tropic hormones target gonads and regulate sex hormones male: androgens like testosterone female: estrogen and progesterone Hormonal control of spermatogenesis is based on negative feedback GnRH in hypothalamus, leads to release of FSH and LH FSH acts on sertoli cells in seminiferous tubules nourish developing sperm LH acts on Leydig cells between seminiferous tubules secrete testosterone, which promotes spermatogenesis Female reproductive has gonads and endocrine Eutherian females must have organs to produce gametes and carry a developing fetus paired ovaries: are the female gonads outer layer of follicles: oocytes (partially developed eggs) surrounded by support cells 12 million follicles at birth after ovulation only 500 mature between puberty and menopause follicle becomes corpus luteum makes estrogen degrades w/o fertilization (menstrual cycle) Oviducts (fallopian tubes) lead to uterus connects to vagina via cervix uterus lining by endometrium many blood vessels to support fetus mammalian females also have mammary glands that produce milk Oogenesis produces a few big cells rather than many small cells, as in spermatogenesis oogonium: diploid (2n) stem cell w/in follicle of ovary primary oocyte: 2n present at birth secondary oocyte: n (+ polar body) fertilized body: 2n (+ polar body) ovulation and sperm initiates meiosis II 2n zygote follicle becomes corpus luteum Ovarian cycle is one of two reproductive cycles Ovarian cycle: produces ovum 28 days under control of same hormones as spermatogenesis 1. GnRH from hypothalamus 2. FSH&LH from anterior pituitary 3. FSH stimulates follicle growth 4. growing follicle secretes estradiol (slowly increases during follicular phase) low estradiol inhibits anterior pituitary 5. BUT increasing estradiol stimulates hypothalamus 6. spike in FSH &LH leads to more The Uterine cycle (menstrual) 7. after ovulation, estrogen stimulate development of uterine lining, including arteries and glands, secretory phase 8. when corpus luteum disintegrates, hormone levels drop, and endometrium degrades, releasing blood menstrual flow phase coordination of ovaries and uterine cycles until menopause Fertilization leads to pregnancy and disrupts cycle Conception sperm fuses with mature oocyte in oviduct 24 hr: first cleavage 23 days zygote reaches uterus 1 week blastocyst implants in endometrium develops into fetus embryo produces HGC, keeps corpus luteum from degrading (produce progesterone) Human gestational period: 38 weeks 1 23 weeks: embryo gets nutrients directly from endometrium placenta forms from embryonic and material tissue blood vessels from both exchange nutrients, gas, waste umbilical= extended circulatory system after 8 weeks, embryo fetus organogenesis ADH AND OXYTOCIN PRODUCED BY POSTERIOR PITUITARY Birth/ labor is induced by estradiol and oxytocin 1. dialation of the cervix 2. contraction of the uterus to push fetus out of vagina 3. more contraction to deliver placenta
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