BIO 1414 Human A & P II

1. BIO 1414 Human A & P II Unit 9 - Reproductive System & Development Robert F. Allen - Professor of Biology

2. Functions: Urination and Copulation Penis

3. Functions: Transport urine & semen Bladder Urethra

4. Function: Maintain temperature of testes approx. 30 C below normal body temp. Scrotum

6. Function: Produce sperm and testosterone Testis

7. Function: Produce Sperm Seminiferous Tubules Testis

8. Testis Cross Section Interstitial Cells Produce Testosterone

9. Function: Sperm storage and maturation Epididymis

10. Function: Transport sperm to urethra Vas Deferens

11. Ejaculatory Duct Function: Produce 60% of alkaline semen including fructose to provide energy for sperm. Seminal Vesicles

12. Function: Produces up to 1/3 of the semen & includes nutrients & enzymes to activate sperm. Prostate

13. Function: Secretes mucous & alkaline buffers to neutralize acidic conditions of urethra. Cowper’s Gland

14. Function: Receives penis & semen and serves as birth canal & passage for menstrual flow. Vagina

15. Function: Provides passageway for sperm, receives blastocyst, retains & nourishes fetus & expells fetus at term. Uterus

16. Function: Cervical mucosa secretes mucous blocking cervical canal entrance to uterus. Cervix

17. Function: Uterine lining in which implantation occurs. Endometrium

18. Function: Muscular contractions. Myometrium

19. Function: Passageway for oocyte and site of fertilization. UterineTubes

20. Function: Produce oocytes & the hormones estrogen and progesterone. Ovaries

21. Function: Sweep ovarian surface to draw oocyte into ovarian tube. Fimbriae

22. Mechanisms of Hormonal Action • Direct Gene Activation • lipid soluble, steroid hormones • diffuse through cell membranes • bind to intracellular receptor • activated hormone receptor/complex binds with gene, turning it on • gene transcribes mRNA • ribosomes use mRNA to synthesize enzymes to stimulate cell activity or synthesize structural proteins to be excreted or used within the cell

23. Direct Gene Activation Steroid Hormone Receptor/hormone Complex

24. Direct Gene Activation Receptor/hormone Complex Protein Aldosterone Cortisol Testosterone Estrogen Progesterone Thyroxine mRNA

25. Mechanisms of Hormonal Action • Second Messenger Systems • amino acid & protein based • cannot pass through cell membranes • bind to cell membrane receptors • activate G proteins in membrane to produce cyclic AMP in cytoplasm • cyclic AMP acts as second messenger inside cell activating protein kinases • protein kinases trigger cellular responses

26. Second Messenger Systems

27. Hormone Sources & Functions • Gonadotropin-releasing Hormone (GnRH) : • Source: Hypothalamus • Targets & Functions: • Females & Males - Anterior Pituitary • Stimulates the production of Follicle Stimulating Hormone (FSH) & Leutinizing Hormone (LH) • Regulates the release of FSH & LH by the anterior pituitary gland

28. Hormone Sources & Functions • Follicle Stimulating Hormone: • Source: Anterior Pituitary • Targets & Functions: • Females - Ovaries • Stimulates follicle growth & maturation • Stimulates estrogen production • Males - Seminiferous Tubules • Promotes sperm production (Spermatogenesis) by establishing testosterone receptors on tubules

29. Leutenizing Hormone: • Targets & Functions: • Females - Ovaries • Stimulates primary oocyte to complete first meiotic division to become secondary oocyte • Triggers ovulation of secondary oocyte • Source: Anterior Pituitary • Transforms ruptured follicle into corpus luteum • Stimulates production of progesterone by corpus luteum • Males - Seminiferous Tubules • Stimulates sperm production (Spermatogenesis) by causing interstitial cells in testes to secrete testosterone Corpus luteum

30. Estrogen: • Targets & Functions: • Body in general • Stimulates the development of female secondary sexual characteristics • Sources: Maturing Follicles & Corpus Luteum • Uterus • Stimulates proliferative phase of uterine cycle • Ovaries • Promotes oogenesis • Breasts • Stimulates development of milk ducts and sinuses (ampullae) • Anterior Pituitary • Stimulates burst-like release of LH

31. Corpus luteum Progesterone: • Targets & Functions: • Females - Uterus • Maintains thickened endometrium • Stimulates nutrient release • Quiets myometrium • Source: Corpus Luteum & Placenta • Females - Breasts • Stimulates development of alveoli for milk production • Females - Anterior Pituitary • Inhibits production & release of FSH & LH

32. Testosterone: • Targets & Functions: • Body in general • Stimulates the development of male secondary sexual characteristics including: • development of male genitalia • male skeleton and muscle development • male patterns for hair growth • increased RBC production & higher metabolic rate • Sources: Interstitial Cells in Testes • Seminiferous tubules • Necessary for the completion of spermatogenesis • Anterior Pituitary • Moderate inhibition of pituitary and hypothalamus

33. Oxytocin: • Sources: Manufactured by hypothalamus. Stored & released by Posterior Pituitary • Positive Feedback Mechanisms: • 1. Childbirth - Stretching of uterus and cervix • 2. Suckling - Milk letdown reflex • Targets & Functions: • Uterus • Stimulates contraction of uterine myometrium causing lowering of fetus & labor • Breasts • Stimulates contraction of milk ducts and sinuses, releasing milk

34. Prolactin: • Source: Anterior Pituitary • Targets & Functions: • Breasts • Stimulates alveoli of breasts to produce milk • Regulation • Release of prolactin by anterior pituitary is regulated by hypothalamus production of Prolactin Releasing Hormone (PRH) & Prolactin Inhibiting Hormone (PIH)

35. Human Chorionic Gonadotropin: • Source: Trophoblasts of blastocyst & Chorion • Target & Functions: • Corpus Luteum • Maintains corpus luteum & causes it to continue producing progesterone in the absence of LH through first four months of pregnancy till placenta produces sufficient estrogen & progesterone to maintain the pregnancy

36. Hormonal Regulation of Ovarian & Menstrual Cycles 1. Hypothalamus releases GnRH. 2. GnRH stimulates anterior pituitary to release FSH. Estrogen FSH 3. FSH stimulates a follicle to grow & produce estrogen.

37. Hormonal Regulation of Menstrual & Ovarian Cycles LH 4. Rising levels of estrogen cause anterior pituitary to increase production & storage of LH. Estrogen Estrogen FSH

38. Hormonal Regulation of Menstrual & Ovarian Cycles 5. High estrogen causes LH to be released in a burst & the endometrium to thicken (proliferative phase). Estrogen Estrogen FSH 6. High LH stimulates first meiotic division of primary oocyte. LH

39. Hormonal Regulation of Menstrual & Ovarian Cycles 7. High LH triggers ovulation. Estrogen Estrogen 8. High LH causes ruptured follicle to become a corpus luteum. FSH LH

40. X X Hormonal Regulation of Menstrual & Ovarian Cycles 9. Corpus luteum produces progesterone. Estrogen 10. Progesterone inhibits the production of FHS & LH by the anterior pituitary & stimulates secretory phase . Progesterone Estrogen FSH LH

41. X X FSH LH Hormonal Regulation of Ovarian & Menstrual Cycles 11. Diminishing levels of FSH & LH cause corpus luteum to deteriorate & produce less progesterone. 12. Dimishing levels of estrogen & progesterone cause inhibition of FSH & LH to end & thickened endometrium to slough (menses). Estrogen Progesterone X

42. Hormonal Regulation of Ovarian & Menstrual Cycles 13. Increasing levels of FSH cause a new cycle to begin. FSH

43. X X Hormonal Regulation in Pregnancy Normally dimishing levels of estrogen & progesterone from deterioration of the corpus luteum would cause thickened endometrium to slough (menses) which would terminating a pregnancy. Estrogen Progesterone X

44. Hormonal Regulation if Pregnancy Occurs Blastocyst produces human Chorionic Gonadotropin (hCG) hormone which maintains corpus luteum in the absence of FSH & LH for the first trimester. hCG Eventually the placenta will produce sufficient estrogen & progesterone to sustain the pregnancy.

45. Mitosis Interphase Prophase Metaphase

46. 46 46 Mitosis Anaphase Telophase Interphase • Most cells of the body - growth, replacement, healing. • No change in the number of chromosomes within each cell.

47. Interphase Prophase Metaphase Meiosis 46

48. Anaphase Telophase Interphase 23 23 Meiosis Reduction Division

49. 23 23 23 23 23 23 Meiosis • Only in gonads. • Synapsis & shuffling of genetic information providing variation. • Results in reduction of number of chromosomes by half (haploid).

50. 23 23 46 46 23 23 23 23 Mitosis/Meiosis Comparison 46 46