Repro- Gonadal Axis F M

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Repro- Gonadal Axis F M
2015-09-13 13:59:04
vetmed repro

vetmed repro
Show Answers:

  1. What is the difference b/w the male and female hypothalamus?
    surge center in female (defeminized in male)
  2. The portal system drains into the ________ only.
    adenohypophysis/ anterior pituitary/ pars distalis
  3. In females, there is a pre-ovulatory ________ surge; in males, there is _________.
    GnRH; tonic GnRH release
  4. How does the hypothalamus communicate with the posterior pituitary?
    direct release of neuropeptides into capillaries of neurohypophysis
  5. 5 Protein hormones.
    oxytocin, GnRH, FSH, Prl, LH
  6. Protein hormones bind to _______ to...
    membrane receptors; activate a signaling cascade.
  7. 3 steroid hormones.
    testosterone, estradiol, progesterone
  8. Steroid hormones cross the ________ to bind to ________ to...
    cell membrane; nuclear receptors; activate transcription.
  9. ________ produce steroid hormones from __________.
    Gonads; cholesterol
  10. The LH surge causes _________ production.
    progesterone (progesterone during pregnancy inhibits new follicles from developing and ovulating--> to sustain current pregnancy)
  11. Describe the pathway of LH in a male.
    hypothalamus--> GnRH--> anterior pituitary--> LH pulse--> leydig cells--> testosterone production--> sertoli cells--> spermatogenesis OR testosterone--> DHT--> circulation OR testosterone--> estradiol
  12. Describe the pathway of FSH in a male.
    hypothalamus--> GnRH--> anterior pituitary--> FSH--> sertoli cell--> ABP (androgen-binding protein)--> ABP binds testosterone in lumen of seminiferous tubules--> accumulutes in lumen--> critical for normal spermatogenesis
  13. Why does ABP accumulate in the lumen of the seminiferous tubules and bind testosterone?
    ABP is too large to pass through the luminal walls
  14. Describe negative feedback of GnRH in males.
    FSH--> sertoli cells--> inhibin and ABP--> inhibin goes to pituitary--> inhibits FSH secretion
  15. Describe the pathway of gonadotropins in a female.
    LH and FSH stimulate follicular growth--> increase in estradiol--> hypothalamus--> GnRH surge--> anterior pituitary--> LH surge--> ovulation
  16. Describe negative feedback of GnRH in females.
    FSH--> follicle produces inhibin--> inhibin goes to pituitary--> inhibits FSH secretion
  17. LH affects _______ cells in a female.
  18. FSH affects ________ cells in a female.
  19. Describe the general pathway for steroid hormones.
    steroid secreted by gonad--> enters blood and goes to target tissue--> causes change in target tissue--> steroid in blood passes through liver--> liver renders steroid water soluble--> steroid re-enters blood--> goes to kidney and bile--> excreted in urine and/or feces
  20. Steroid hormones are metabolized in the _________.
  21. After steroid hormones have been metabolized, they are excreted as __(2)__.
    glucuronide or sulfate
  22. Primordial germ cells develop in the ________; they then migrate to the _______ and then the ________.
    yolk sac; hindgut; undifferentiated gonad
  23. Primary oocytes increase in number right after __________; subsequently, they decrease in number by _______.
    fertilization; atresia and ovulation (after puberty, until menopause)
  24. Describe the series of events that occur during maturation of a primordial germ cell to a zygote.
    [primordial germ cell] mitosis--> [oogonia] mitosis--> [primary oocytes] mitosis then meiosis--> [4n primary oocytes] nuclear arrest  at meiotic prophase--> [after puberty] LH surge (meiotic inhibitors removed)--> meiosis resumes--> [secondary oocyte] meiosis is arrested at metaphase--> [secondary oocyte] ovulation]--> fertilization---> sperm trigger completion of meiosis--> zygote
  25. Primordial germ cells and oogonia are ________ (number of chromosomes).
  26. Primary oocytes goes from _______ to ________ (number of chromosomes).
    2n (diploid); 4n
  27. The secondary oocyte is __________ (number of chromosomes).
  28. The second meiotic division occurs after __________, but meiosis is arrested at __________ until _________.
    ovulation; metaphase; fertilization
  29. Meiosis is arrested at the ________ and _________ stages.
    4n primary oocyte; 2n secondary oocyte
  30. Describe the maturation of a primary oocyte to a follicle.
    primary oocyte--> primordial follicle--> primary follicle--> secondary follicle--> early tertiary follicle--> graafian follciel
  31. Granulosa cells and the zona pellucida don't develop until the ________.
    primary follicle
  32. Theca cells don't develop until the ________.
    secondary follicle
  33. The corona radiata and cumulus oophorus are features of the _________.
    graafian follicle
  34. The antral follicle continues to grow until it produces enough _______ to cause a(n) ________, which causes _________.
    estradiol; LH surge; resumption of meiosis
  35. When theca cells undergo lutinization, they switch from producing _________ to producing _________.
    estradiol; progesterone
  36. After lutinization occurs, if the animal is not pregnant, theca cells begin producing _________, and a ________ forms.
    prostaglandin; corpus albicans
  37. What part of the oviduct does fertilization occur?
  38. What is unique about the equine ovary?
    only a small area is germinal epithelium (ovulation fossa); in other species, the entire surface is covered with germinal epithelium
  39. What is unique about the canine ovary?
    ovarian bursa
  40. What is unique about the canine cervix?
    it opens dorsally