Reproductive System

1. Reproductive System • Gonads develop from genital ridges of mesoderm, just medial to kidneys • Germinal epithelium will form the gametes

2. Male - Testes • Seminiferous tubules are coiled tubules lined with germinal epithelium & make sperm in most vertebrates • A few fish, cyclostomes, urodeles lack seminiferous tubules and make sperm in cysts that collapse upon spawning

4. Location of testes • Abdominal cavity in monotremes, elephants, whales and non-mammals • Descended permanently in ungulates, carnivores, humans • Rectractile in rabbits, lower primates

5. Testes • Sperm pass through the vasa efferentia in a closed system to the • Vas deferens = spermatic duct = mesonephric duct

7. Vas deferens empties into cloaca below placental mammals and • Urethra = Urogenital sinus in placental mammals

10. Copulatory Organs • Needed to introduce sperm into females for internal fertilization • Claspers in elasmobranchs – modified pelvic fin

12. Copulatory Organs • Gonopodium – teleosts – modified anal fin

14. Copulatory Organ • Hemipenes in snakes and lizards • Can protrude

16. Copulatory Organs • Penis • Erectile tissue • Turtles, crocodiles, monotremes, some birds have a penis as a thickening on floor of cloaca • Placenta mammals have an external penis

18. Female Gonad - Ovary • Hollow, but lined with germinal epithelium in teleosts

20. Ovary • Thin-walled sacs in anurans and urodeles • Fluid-filled lacunae in reptiles, bird, monotremes • Solid in mammals, containing follicles

22. Ovulation • Into coelom, open system

24. Oviducts, Uterus, Vagina • Develop from Muellerian Ducts in most

26. Oviducts, Uterus, Vagina • Empty into cloaca below placental mammals • May be specialized in some areas

28. Hen

29. Placental mammals • Uterus variations • Marsupials have 2 • Most placental mammals have horns for multiple births • Cervix – caudal-most muscular opening to vagina

32. Placental Mammals • Vagina • The vagina, a cloacal derivative, empties into the urogenital sinus in most placental mammals • The vagina opens directly to the vulva in rodents and primates

35. Cloaca • The cloaca, or vent, receives intestine and urogenital structures in all vertebrates except placental mammals

37. Cloaca • Urorectal fold is present in reptiles, birds and monotremes • It begins to divide the cloaca • Coprodeum – collects digestive waste dorsally • Urodeum – collects urine ventrally • Proctodeum – common, undivided, terminal

39. Cloaca • Cloaca divides into urogenital sinus and rectum in all placental mammals except female primates & rodents • Urethra, vagina, rectum in female primates & rodents

41. Key Points • Is the cloaca a correct term to use when discussing the mammal? Why or why not?

42. Key Points • What is meant by the reproductive system in the male being a closed system and the female being an open system?

43. Key Point • Gonads make gametes. Name the gonads and gametes for each sex.