Urogenital System Part 2 PDF

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Urogenital System Part II A. Sex a. Testosterone stimulates the development of the Wolffian Duct into the vas deferens, epididymis, prostate, seminal vesciles, etc. i. Testes produce anti-mullerian hormone that inhibits MD development ii. Wolffian Duct = Archinephric Duct b. In females, the Mullerian duct becomes the oviduct, uterus, and vagina and the Wolffian duct regresses c. Remnants of Opposite Sex in Humans i. Males – prostatic utricle and appendix tubes of unknown function ii. Females – Epoophoron, Paroophoron, and Gartner’s ducts B. Sex Development a. Paired gonads arise from genital ridge (thickening of splanchic mesoderm) b. Germ cells arise from extraembryonic endoderm and migrate to indifferent gonad i. Female cells to cortex ii. Male cells to medulla C. Female Reproductive System a. Ovary – produce eggs b. Funnel (ostium) delivers eggs to oviduct c. Uterus – holds eggs prior to laying or young d. Uterus – expanded portion of oviduct e. Shell gland – add more yolk or shell f. Hagfish and lampreys i. Single large ovary suspended middorsally ii. Hagfish – 1 develops iii. Lampreys – fusion iv. No oviduct v. Eggs released in coelom vi. Secondary pores to anus (hagfish) or cloaca (lamprey) g. Chondrichthyes i. May have just one ovary ii. Always one in chimaers iii. May store sperm iv. Secretes albumen and mucus v. Oviparous – egg case vi. Viviparous – may be indistinguishable vii. Nutritionally support young if held for a while viii. 2 separate exits or combine h. Early Bony Fishes i. Same ii. No shell gland or uterus

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Teleosts i. May release eggs into coelom 1. Then short funnel remnant at posterior part of coelom ii. Mullerian duct regresses, regression complete in derived teleosts 1. Derived – New ovarian duct from peritoneal folds a. Direct to vent iii. Most lay eggs iv. Viviparity – live bearing evolved multiple times v. Guppies are weird 1. Fertilization occurs when eggs are still in their follicles 2. Atretic Oocytes a. Those that fail to be fertilized b. Reabsorbed to provide nutrition for survivors j. Tetrapods i. Ovaries usually paired ii. New Metanephric duct – ureter 1. Archinephric duct regresses iii. Oviducts may have prominent sheets of smooth muscle iv. Oviparous – prominent shell gland v. Viviparous – distinct uterus D. Female Reproductive Anatomy a. Oviduct i. Fimbria move ovum to oviduct after fertilization (internal) or to oviduct for external fertilization ii. Shell gland – add layers of shell or nutrition 1. Has to be after fertilization 2. Reptiles – add albumin, shell membrane, then hard shell iii. Shelled egg held until ready to be laid b. Uterus i. Terminal portion of oviduct ii. Hold shelled eggs or embryos iii. Placenta – extraembryonic membranes of embryo establish vascular association 1. Placental mammals as well as some marsupials, amphibians, fishes, and reptiles iv. Chorioallantoic placenta – unique to placental mammals, but these types of allantoic placentae common in other amniotes c. Placenta i. Evolved multiple times d. Monotremes – Uterus i. No vagina or cervix ii. Duplex uterus = shell gland iii. Urogenital sinus 1. Urethra and uteri combine e. Metatherians – Uterus i. Duplex uterus

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ii. 2 Vaginas, 2 Cervices 1. Some with vaginal sinus like opossum 2. Some with median birth canals like kangaroos Eutherians i. Wide variety ii. Shows gradual fusion of uterine horns in several groups iii. Duplex – rodents and rabbits 1. 2 horns and cervices 2. Urogenital sinus a. Urethra and vagina combine iv. Bipartite – pigs, marine mammals, mice, carnivores 1. Small body 2. 2 horns, 1 vagina, 1 cervix v. Bicornuate – most bats, artiodactyls & perissodactyls 1. Artiodactyls – cows, deer, pigs 2. Perrisodactyls – horses, rhinos, tapirs 3. Large body, short horns vi. Simplex – higher primates 1. Horns fused 2. Urethra and vagina generally separate

E. Spermatogenesis a. Fishes & Amphibians i. Within a cyst or follicle ii. Spermatogonia reproduce clonally in cysts – spermatocytes iii. All cells undergo spermatogenesis in unison b. Amniotes i. Spermatogonia in wall of seminiferous tubule splits, one of which will undergo spermatogenesis c. Hagfish & Lampreys i. Sperm shed into coelom ii. Exit via abdominal pores iii. Archinephric ducts just drain kidneys d. Elasmobranchs i. Mullerian ducts rudimentary ii. Kidney has reproductive and urinary section iii. Distinct accessory urinary ducts to uriniferous kidney iv. Reproductive kidney with short tubules connecting testis to archinephric duct 1. Tubules = epididymis 2. Archinephric duct only for sperm – vas deferens e. Bony Fishes i. Archinephric duct may receive urine and sperm ii. Most teleost – testicular duct may have own opening iii. Some (salmonids) lack a duct, release sperm in coelom and out through pores in lower coelom

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Amphibians i. Necturus and some others – archinephric duct for urine and sperm 1. Most with accessory urinary ducts and vas deferens ii. Most salamanders with reproductive kidney iii. Frogs without it g. Amniotes i. Always have vas deferens ii. Several Mesonephric tubules form epididymis iii. Kidney drained by ureter F. Scrotum a. Testes descend into outpocketing of coelom in most mammals b. Connected by inguinal canal c. Some just temporary d. Remain in body cavity in some e. Or descend into muscular pouch but not true scrotum G. Copulation a. Primitively- release sperm over eggs b. If a uterus houses young or a shell is added, internal fertilization required i. Salamanders – produce spermatophore that female picks up c. Most with an intromittent organ – possessed by male to provide sperm during sex H. Intromittent Organs a. Claspers – sharks, placoderms i. Pelvic fins inserted into females ii. Siphon pumps sperm down grooves in pelvic fin iii. Many Teleosts – modification of anal fin iv. Gonopodium of guppies and other live bearers v. Sometimes modified genital papilla b. Amniotes – generally have a penis, but not homologous across groups i. Remarkably convergent in anatomy ii. Single, Median in turtles, crocodiles, and mammals iii. Turtles & Crocs – from ventral cloacal wall iv. Mammals – from non-cloacal epithelium and connective tissue v. Double (Hemipenes) in tuataras, snakes, and lizards from lateral cloacal wall vi. Absent in most birds (except ducks and ratites, from ventral cloacal wall, but use lymph system c. Mammals – penis is bifurcated in monotremes and marsupials i. Baculum – penis bone or os penis 1. Present in most mammals a. Except humans, horses, marsupials, lagomorphs, and hyenas 2. Normally held in the abdominal cavity 3. Slides into penis prior to sex for near instant erection

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4. Female homolog – baubellum or os clitoris Urinary Bladder a. Urine is generally stored before release b. Fishes – mesodermal and noncloacal i. Chondrichthyes and most teleosts c. Tetrapods – diverticulum (outpocketing) of cloaca i. Lost in snakes, some lizards, croc, and birds (except ostriches) d. Therian Mammals – ureter drains directly into it Lithopaedia, Ectopic Pregnancies, and Endometriosus a. In all gnathostomes except teleosts, ovary is separate from oviduct i. Eggs float through body cavity on current within oviduct b. Endometriosis is when the endometrium has sloughed off and enter the coelom i. Found all over body ii. Caused by position of the ovary c. Ectopic pregnancies is when the egg that is normally fertilizaed in the fallopian tube and drifts to uterus to implant, is implanted elsewhere i. Usually in fallopian tube ii. Rarely viable d. Abomdinal pregnancies – when embryo implants on tissue with rich circulation i. C-section necessary but usually kills both e. Lithopaedia – stone child i. Body will calcify foreign tissues ii. Seals off baby, but left as rock inside mother...