1. Human Reproduction and Development

2. Human Reproduction: It’s all about babies!

3. The MALE reproductive system

4. Sperm cells are made in the TESTES. The testes also produce the hormone testosterone.

5. Cross section of a seminiferous tubule in the testes. The immature sperm are at the edges and move toward the center during meiosis to produce sperm cells.

6. Testes are housed outside of the body in a pouch called the SCROTUM which controls the temperature of sperm development.

8. Immature sperm cells travel to the EPIDIDYMIS where they are stored and where they mature. Sperm cells make up less than 5% of semen.

9. Tubes called the VAS DEFERENS carry sperm cells on their way out of the body during ejaculation.

10. The SEMINAL VESICLES produce a slightly basic, sugar-rich fluid for sperm cells to swim in. About 65% of semen comes from SVs.

11. The PROSTATE GLAND adds a fluid containing protective proteins that help the sperm cells to survive. About 30% of semen comes from the prostate gland.

12. The URINARY BLADDER temporarily stores urine.

13. The URETER carries urine made in the kidneys to the urinary bladder.

14. The BULBOURETHRAL GLAND produces a slightly basic fluid that cleans the urethra. The fluid is released prior to ejaculation (and can carry leftover sperm in the urethra).

15. The URETHRA is a tube where either urine or sperm- containing semen can leave the body.

16. The PENIS is inserted into the female during intercourse to deposit sperm cells. It contains columns of erectile tissue which, depending on he flow of blood, can make the penis flaccid or erect.

17. Trace the path of sperm through the male reproductive system: 1.Sperm are produced in the TESTES, 2.stored in the EPIDIDYMIS (where they mature), 3.move through the VAS DEFERENS, and 4.pass out of the body through the URETHRA.

18. * Hormone levels remain relatively constant in males, unlike females. * The pituitary releases FSH and LH * LH and FSH stimulate testosterone and sperm production in the testes * Higher testosterone levels inhibit the production of FSH and LH. Explain how this “negative feedback loop” maintains constant levels of hormones. Hormones in the Male Reproductive System

19. Functions of Testosterone

21. Human sperm cells under the light microscope.

22. The FEMALE reproductive system

23. The Female System

24. Cervix The CERVIX is a ring of muscle between the uterus and the vagina that allows sperm cells to enter, menstrual blood to flow, and dilates to 10 cm diameter during labor to allow childbirth.

25. The Female System Ovary The OVARIES are where the ova (eggs) are produced. They also produce the important hormones estrogen and progesterone.

26. The image shows stages of egg development in an ovary. The eggs DO NOT travel around the ovary; they stay in one place. The image indicates change over TIME (during a one month menstrual cycle), not location.

27. The Female System Fallopian Tube The FALLOPIAN TUBE (oviduct) carries the ovum to the uterus. It is the site of fertilization (sperm and egg combine)

28. The Female System Uterus The UTERUS is a very strong muscle that supports the developing embryo /fetus. It contracts to push the baby out during labor.

29. The Female System 4a.Endometriu m The lining of the uterus where the embryo implants and the placenta grows.

30. The Female System Urinary Bladder Urine is stored here temporarily.

31. The Female System Urethra Urine leaves the body through this tube.

32. The Female System Vagina During intercourse sperm cells are deposited here. During birth the baby passes through here.

33. The Female System 8. Vulva External female genitalia. Roles include sexual pleasure and protecting the vaginal opening.

34. Hormones in the female reproductive system THE MENSTRUAL CYCLE: From puberty (average age 13) to menopause (average age 50), a monthly cycle preparing the uterus for pregnancy and releasing an egg. Does not occur during pregnancy. Involves four hormones: From the pituitary: 1. FSH = follicle stimulating hormone 2. LH = luteinizing hormone From the ovary: 3. Estrogen 4. Progesterone

35. Hormones in the female reproductive system Pituitary hormones Follicle development Ovarian hormones Endometrium thickness

36. Menstrual Cycle Interactive Click on the image above to go to the website.

37. 1. Follicle Stimulating Hormone (FSH) FSH Causes an ovum to develop inside a follicle Causes the follicle to secrete estrogen

38. 2. Estrogen EST causes the endometrium to thicken At a critical level, causes the release of LH (also produced by the placenta during pregnancy)

39. 3. Luteinizing Hormone (LH) LH causes the follicle to rupture and release the ovum (ovulation) The follicle becomes the corpus luteum, which produces progesterone and estrogen

40. Ovulation: Follicle rupturing and releasing an egg.

41. An ovum travelling down the inside of a fallopian tube (oviduct)

42. 4. Progesterone PRO Produced by the corpus luteum (and placenta) maintains and further thickens the endometrium Inhibits FSH

43. Hormone Levels in the Menstual Cycle PRO EST FSH LH The corpus luteum begins to break down after ~10 days (unless a pregnancy begins) so progesterone levels fall The endometrium lining is shed (menses / menstrual flow) Low levels of progesterone allow FSH to rise and the cycle repeats

44. Review: explain the key events in the menstrual cycle.

45. When MALE and FEMALE gametes come together

46. Fertilization: male and female gametes combine Top left: Sperm attempting to enter egg cell Top right: Gametes fuse. Success! Bottom left: A zygote. Notice the two nuclei – one from the sperm and one from the egg.

47. Embryonic Development IMPLANTATION: the embryo attaches to the endometrium.

48. Embryonic Development Early embryonic development (0-6 weeks)

49. Embryonic and Fetal Development *counting from last menstruation (2 weeks = fertilization)

50. Placenta: The bridge between mother and fetus The placenta: Shape and size of a dinner plate Exchanges food, waste, hormones, oxygen, drugs, and more between the blood of the mother and fetus (which do not touch). Takes over production of estrogen and progesterone from the corpus luteum.

51. Labor and Delivery 1.Cervix dilates from 0-10 cm diameter, 2. baby delivered through vagina, 3. placenta delivered through vagina.

52. After a little meiosis, a lot of mitosis, fertilization, implantation, etc… The sweetest little diploid 46 XX you ever saw! (says Mr. Schoonover with some bias)