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Ovulation

Discussion in 'DAT Discussions' started by arpitpatel86, May 16, 2008.

  1. arpitpatel86

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    on shaum's bio book page 175 it says that "At the time of ovulation (release of the ovum) there is a sharp drop in estradiol and a surge in LH levels."

    there was a question on top score that asked

    During the ovarian ovulation phase, you would expect:

    A. increase estrogen followed by decrease progesterone

    B.increase estrogen followed by decrease in LH

    c.increase in estrogen followed by surge in LH

    D. decrease in estrogen followed by increase in progesteron

    E. decrease in estrogen followed by surge in LH

    the answer according to top score was C.....but according to shaum's bio shoulding it be E

    the kaplan blue book would say C as well so is shaum's bio book wrong? or am i just not getting something.

    Also, would answer D go with the luteal phase?
     
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  3. Zerconia2921

    Zerconia2921 Bring your A-game!

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    Point 1: Follice via from FSH secrets estrogen until ovulation occurs. This causes spike in LH that regulated estrogen secretion. So estrogen levels will increase at the time of ovulation. LH spike reduced estrogen level then.

    Point 2: The ruptured follicle is induced to become the corpus luteum which secretes progesteron in large for implant. (Also little estradiol secretes estrogen also) but major point to remember corpus luteum --> progesteron.

    Point 3: If no fertilization occurs levels of estrogen and progesteron drop.

    To your question. C is correct because for the follicle to have ovulated there must have been a surge of estrogen and then followed by the spike of LH to lower estrogen levels.

    Choice D is wrong because that talks about the Luteal phase where corpus luteum secretes progesteron.
    Choice E is wrong because a decrease in estrogen will not cause the follicle to ovulate there must be an increase of estrogen.

    Hope i made sense.
     
  4. AFF2009

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    [​IMG]
    I agree it's E
     
  5. arpitpatel86

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    thanks for your reply.....but of those posts makes sense? so what is the correct answer C or E?
     
  6. Zerconia2921

    Zerconia2921 Bring your A-game!

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    I thought i gave a good explanation but i guess it didnt stick. The answer is STILL C.
     
  7. arpitpatel86

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    ok lets see if i got it..............in the process of getting to the ovulation phase there must be an increase in estrogen for there to be a spike in LH....as soon as we hit this spike, the estrogen levels drop?


    E is not right because you cant have a spike in LH if there is a drop in estrogen first righ?
     
  8. Zerconia2921

    Zerconia2921 Bring your A-game!

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    You my friend are CORRECT! :thumbup:
     
  9. dentalplan

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    I think the answer is C because the answer was: an increase in estradiol FOLLOWED by an LH surge. As you can see from the graph, the decrease in estradiol occurs DURING the LH surge, not before it. So answer C makes sense.

    E doesn't make sense because it's simply not true. A decrease in estradiol does not mean an LH surge will follow. Decreased estradiol occurs during the LH surge -- i.e. a decrease in estradiol occurs while the LH surge is occuring (like Shaum's said). However, it is an estradiol increase that occurs first. Then, secondly, there is an LH surge that follows. Only DURING the LH surge, there will be decrease in estradiol, not before it.
     
  10. userah

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  11. petra23

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    Cool article...
     
  12. DCRedskinsRule

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  13. mcdds75

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    The answer is absolutely C b/c LH SURGE causes ovulation, during the early to mid follicular phase the HPG axis is in neg. feedback where estrogen is increasing slowly until the pre-ovulatory phase where the HPG is in PFB and everything rises quickly (E2 reaches threshold). E2 must rise in order for the granulosa cells to proliferate in the follicle. I promise the answer is correct!! Also, E2 must increase first to increase receptors
     

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