1 / 23

HORMONES!

HORMONES!. Hormones Involved in Reproduction - MALES. ● Androgens : produced by Leydig cells in testes -ex: testosterone ● GnRH : from hypothalamus; regulates release of FSH and LH from pituitary

emilie
Download Presentation

HORMONES!

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. HORMONES!

  2. Hormones Involved in Reproduction - MALES ● Androgens: produced by Leydig cells in testes -ex: testosterone ● GnRH: from hypothalamus; regulates release of FSH and LH from pituitary ● FSH: acts on Sertoli cells of seminiferous tubules to promote spermatogenesis ● LH: stimulates Leydig cells to produce testosterone (stimulates sperm production)

  3. *PRIMARY SEX CHARACTERISTICS (associated with the reproductive system: -development of internal and external reproductive organs -sperm production

  4. * SECONDARY SEX CHARACTERISTICS : -deepening of voice -distribution of facial & pubic hair -muscle growth

  5. Hormones Involved in Reproduction - FEMALES ● Estrogen: produced by growing follicle ● Progesterone: inhibits release of FSH & maintains blood vessels in uterine lining ● GnRH: from hypothalamus; regulates release of FSH and LH from pituitary ● FSH: acts on follicle in ovary to continue oogenesis ● LH: stimulates follicle to rupture (causes ovulation)

  6. Hormones Involved in Reproduction - FEMALES ● 2 parallel cycles controlled by these hormones 1) OVARIAN CYCLE = changes that occur in ovaries 2) MENSTRUAL CYCLE = changes that occur in uterus

  7. Ovarian Cycle (3 phases): • Follicular phase: time during which several follicles in ovaries begin to grow • Cycle begins with release of GnRH stimulates the pituitary to secretes FSH & LH • FSH stimulates the follicle to grow • Growing follicle produces estrogen (Follicular phase)

  8. Ovarian Cycle: • Ovulatory phase: follicle & adjacent wall of ovary rupture, releasing the egg (2° oocyte) • Steep increase inestrogen increases release of GnRH • GnRH increases secretion of FSH & LH (LH surge!) • Follicle has more LH receptors & LH induces final maturation & ovulation

  9. Ovarian Cycle: 3)Luteal phase: the remaining follicular tissue in ovary after ovulation becomes the CORPUS LUTEUM (C.L.) which is endocrine tissue that secretes hormones • LH stimulates transformation of follicular tissue to C.L. • C.L. secretes estrogen & progesterone • Combination of these hormones exerts negative feedback on hypothalamus & pituitary (Luteal phase)

  10. Near the end of the Luteal Phase, C.L. disintegrates • Decreases estrogen & progesterone which “liberate” hypothalamus & pituitary from inhibitor effects • GnRH can now be secreted (then FSH & LH) **The cycle begins again!**

  11. Menstrual cycle also occurs in 3 phases: 1) Menstrual flow phase (3-5 days): time during which endometrium is being shed from uterus (1st day of menstruation =Day 1 of both cycles)

  12. Menstrual cycle: 2) Proliferative phase (1-2 weeks): involves regeneration & thickening of endometrium • Caused by the estrogen secreted from the follicles • After ovulation, secreted estrogen & progesterone stimulate continued development & maintenance of the endometrium

  13. Menstrual cycle: 3) Secretory phase (2 weeks): endometrium continues to thicken (due to estrogen & progesterone); it becomes more vascularized & develops glands which secrete a glycogen rich fluid which serves as nutritional fluid for the embryo

  14. IF embryo does NOT implant in uterine lining by the end of this phase, a new menstrual flow phase begins • Disintegration of the C.L. reduces blood flow to the endometrium  the endometrium breaks down & passes out of the uterus (back to Menstrual Flow Phase) • IF embryo is present, it secretes HCG which maintains estrogen & progest. secretion by the C.L. so the endometrium is maintained

  15. *primary sex characteristics: associated with the reproductive system -development of internal and external reproductive organs -egg production

  16. *secondary sex characteristics: -increases fat deposition in breasts & hips -increases water retention -affects calcium metabolism -stimulates breast development

  17. MENOPAUSE Menopause: cessation of ovulation and menstruation -between ages of 46 and 54 -ovaries lose their responsiveness to FSH/LH -results from decline in production of estrogens

More Related