Biology 30

1. Biology 30 Hormonal Control of Reproduction Conception, Pregnancy, Development, Birth

2. Did You Know? Whistling is rated the number one subconcious way to attract the opposite sex

3. Hormonal Control of Reproduction • Male Reproductive System Control • Testosterone • Primary Function • Stimulate spermatogenesis • Secondary Function • Maturation of testes and penis • Sex drive • Facial hair • Body hair • Deeper voice • Increased muscle strength • Body oil secretion -- acne

4. Hormonal Control of the Testes • Hypothalamus releases • Gonadotropin-Releasing Hormone (GnRH) • Stimulates pituitary to release LH & FSH • Pituitary releases • Follicle-Stimulating Hormone (FSH) • Stimulates spermatogenesis by seminiferous tubules • Luteinizing hormone (LH) • Stimulates testosterone production by interstitial cells • Indirectly stimulates spermatogenesis because testosterone is required for sperm production.

5. Hormonal Control of the Testes LH, FSH, and GnRH concentrations in the blood are controlled by negative feedback systems

6. Not enough testosterone in the blood. GnRH LH FSH Testes

7. Not enough testosterone in the blood. GnRH ICSH FSH Testes

8. Not enough testosterone in the blood. GnRH ICSH Testosterone production Spermatogenesis FSH

9. GnRH Testosterone ICSH FSH Inhibin Testosterone production Spermatogenesis

11. Believe it or not… Simon (Sime-one), Tom Green, Nick Fitio, (Calgary Flames) John Kruk, (Phillies) Hitler and Napoleon were missing one testicle.

12. Hormonal Control of Female Reproduction • Hypothalamus - produces releasing GnRH • Anterior Pituitary – secrete gonadotropic hormones. • FSH - follicle stimulating hormone. • LH - luteinizing hormone. • Ovaries - secrete the female sex hormones. • Estrogen –thickening of uterine lining • Progesterone – matures/maintains uterine lining

13. Hormonal Control of Reproduction • FSH is released from AP • Start the ripening of ovum within follicle • Estrogen is produced by follicle • Development of endometrium for possible pregnancy • Feedback to hypothalamus to inhibit FSH and release LH

14. Hormonal Control of Reproduction • LH surge on day 14 • Stimulates ovulation • Conversion of follicle into corpus luteum • Progesterone production • Continued development of endometrium • Feedback to inhibit release of LH

15. Hormonal Control of Reproduction • If no fertilization • Degeneration of corpus luteum • Drop in hormone level

16. Menstruation The four phases

19. Four Phases of Menstruation 1. Flow Phase (Menstrual Phase) • Start of bleeding marks Day 1 of phase • Shedding of the endometrium (uterine lining) • Average = 4-5 days • Sometimes up to 8 days • Occurs due to low hormone levels

20. 1

21. Four Phases of Menstruation • Follicular Phase • Occurs during day 6-13 • Period of repair and thickening of endometrium.

23. Four Phases of Menstruation • Follicular Phase • Occurs during day 6-13 • Period of repair and thickening of endometrium. • FSH from the pituitary promotes follicle development in the ovary.

25. Four Phases of Menstruation • Follicular Phase • Occurs during day 6-13 • Period of repair and thickening of endometrium. WHY?? • FSH from the pituitary promotes follicle development in the ovary. • As follicle develops it produces estrogen, • thickening of the uterine lining • LH production increase • FSH production decrease

26. FSH Decrease

27. Four Phases of Menstruation • Ovulation Phase • LH causes ovulation to occur on day 14. • Secondary oocyte is released from the follicle/ovary.

29. Four Phases of Menstruation • Luteal Phase • Final preparation of endometrium to receive the fertilized ovum • LH stimulates development of the Corpus Luteum. • causes progesterone levels to increase.

31. Four Phases of Menstruation • Luteal Phase • Final preparation of endometrium to receive the fertilized ovum • LH stimulates development of the Corpus Luteum. • causes progesterone levels to increase. • Estrogen and progesterone inhibit GnRH, thereby decreasing LH and FSH levels. • This low level of hormones initiates the flow phase.

32. GnRH

33. Builds Uterine Lining Maintains Uterine Lining Ovulation & Corpus Luteum Formation

35. Menopause • The end of a woman’s reproductive years • Between ages of 45 – 55 • Ovaries no longer respond to FSH & LH from AP • Ovaries do not produce estrogen or progesterone • Marked by circulatory irregularities (hot flashes), dizziness, insomnia, sleepiness, depression • Hormone replacement therapy may help.

36. Did You Know? Lions will have sex over 500 times with one mate. This is to ensure fertilization.

37. Fertilization Pregnancy Development Birth

38. Sperm

39. Did You Know? Sperm travels at .001 miles per hour.

41. 3 Steps of Fertilization • Capacitating • Acidic environment of the female reproductive tract causes small pores to open in the acrosome (“enzyme-loaded” head) of the sperm

42. Acrosome

43. 3 Steps of Fertilization • Capacitating • Acidic environment of the female reproductive tract causes small pores to open in the acrosome (“enzyme-loaded” head) of the sperm • Acrosomal reaction • Enzymes released from acrosome digest the outer membrane surrounding the egg cell

44. Steps of Fertilization • Fertilization • A single sperm cell fuses with the plasma membrane of ovum • Head passes into the cytoplasm • Electrochemical reaction in egg • Makes membrane impermeable to other sperm

45. Fertilization • Fertilization must occur within a very short window of opportunity. • Egg is only fertile for 10 - 15 hours • Sperm are only fertile for 48 hours • Sex (copulation) must occur no more than 48 hours before or 15 hours after ovulation

46. NO KIDDING Italian physicians promotes having regular sex with the same partner because it is good for digestion. He also states that having casual sex with many partners can cause indigestion.  

47. Pregnancy • If pregnancy is established, menstruation does not occur. • Fertilized egg is called a zygote. • Once cell division brings the total cell count to around 8, it is called a blastocyst. • Takes 3-5 days for blastocyst to travel through oviduct to uterus. • Blastocyst must implant into endometrium • Occurs 2-4 days after reaching the uterus

48. Zygote

49. Cleavage

50. Blastocyst