Jonkst

Senior Member
15+ Year Member
Mar 20, 2002
209
0
Florida
Visit site
Status (Visible)
Quick question about a Biology topic:
Can anyone explain the menstrual cycle stuff. I have yet to find a source that explains it well.

I have a feeling I'm going to get some interesting responses to this one...
 

rCubed

taiko master
10+ Year Member
15+ Year Member
Jul 15, 2002
416
0
NY
Visit site
Status (Visible)
hmmm...let me take a stab at it

first of all, remember...estrogen will stimulate gonadotropin releasing hormone (GnRH) which will stimulate LH and FSH

however, estrogen and progesterone together inhibit GnRH which in turn inhibits LH and FSH


ok, step by step:

I. Follicular phase: FSH and LH are both being secreted, this is just after the woman has completed menstration. FSH and LH at this point develop ovarian follicles which in turn secrete estrogen, which will stimulate GnRH, which will stimulate even more LH and FSH

II Ovulation: Now we have alot more LH which stimulate ovulation, or release of the egg from the ovary....

III Luteal phase: now there's still all that LH and it acts on the follicle to develop it into the corpus luteum. the corpus luteum secretes estrogen and progesterone. both of these together will not only cause the endometrium to develop and vascularize, they'll make the LH and FSH secretions stop

IV Menstration: this occurs only if there is no fertalization. the corpus luteum degenerates, thus no more progesterone and estrogen..so no more thick uterine lining, so menstration occurs. and since the corpus luteum just degenerated, and theres no more estrogen and progesterone together, LH and FSH can be secreted again



hope that sort of helps, its a really short overview
 

Jonkst

Senior Member
15+ Year Member
Mar 20, 2002
209
0
Florida
Visit site
Status (Visible)
Thanks rCubed. I appreciate it. Simple is fine; all I need for the MCAT anyway. "thus no more progesterone and estrogen" was all I needed to clear it up.

Good luck to ya'
 
About the Ads
This thread is more than 18 years old.

Your message may be considered spam for the following reasons:

  1. Your new thread title is very short, and likely is unhelpful.
  2. Your reply is very short and likely does not add anything to the thread.
  3. Your reply is very long and likely does not add anything to the thread.
  4. It is very likely that it does not need any further discussion and thus bumping it serves no purpose.
  5. Your message is mostly quotes or spoilers.
  6. Your reply has occurred very quickly after a previous reply and likely does not add anything to the thread.
  7. This thread is locked.
About the Ads