Menstrual Cycle Q

[TawMus]

During the Menstrual Cycle, the sudden surge of LH causes ovulation to occurs. But if the secretion of LH is inhibited by the presence of estrogen, then won't the simultaneous increase in estrogen prevent a surge of LH from happening??

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[BloodySurgeon]

During the Menstrual Cycle, the sudden surge of LH causes ovulation to occurs. But if the secretion of LH is inhibited by the presence of estrogen, then won't the simultaneous increase in estrogen prevent a surge of LH from happening??

at around 12-13 days of a women's menstrual cycle there is a positive feedback of LH and FSH which causes more estrogen and even more LH and FSH. This creates a LH surge by day 14 and ovulation occurs. This in return creates a corpus luteum that creates a negative feedback of LH and FSH (so no more follicles are created) and the corpus luteum promotes the secretion of estrogen and progesterone (which thickens the lining of the uterine endometrium for implantation). If there is no implantaion by the 28th day the corpus luteum atrophies and FSH is created. This creates the follicle and the markes the begining of the mentrual cycle. For the first five days the women menstrates which is when the endometrium sloughs off and "bleeds."

Which now makes me curious of another question. Can you make a girl pregnant if you sleep with her while she is on her period? Although the endometrium is sloughing and the corpus luteum has atrophy, if that fertilized egg reaches the uterus it could be etopic or just implant itself somewhere (especially since not every girl is regular and you could never really know where she is on her mentrual cycle). If that zygote get implanted then it can produce HcG and bring that thick wall back with a release of estrogen and progesterone. So is the myth false? Can you impregnate a women on her period?

 

[TawMus]

at around 12-13 days of a women's menstrual cycle there is a positive feedback of LH and FSH which causes more estrogen and even more LH and FSH. This creates a LH surge by day 14 and ovulation occurs. This in return creates a corpus luteum that creates a negative feedback of LH and FSH (so no more follicles are created) and the corpus luteum promotes the secretion of estrogen and progesterone (which thickens the lining of the uterine endometrium for implantation). If there is no implantaion by the 28th day the corpus luteum atrophies and FSH is created. This creates the follicle and the markes the begining of the mentrual cycle. For the first five days the women menstrates which is when the endometrium sloughs off and "bleeds."

Which now makes me curious of another question. Can you make a girl pregnant if you sleep with her while she is on her period? Although the endometrium is sloughing and the corpus luteum has atrophy, if that fertilized egg reaches the uterus it could be etopic or just implant itself somewhere (especially since not every girl is regular and you could never really know where she is on her mentrual cycle). If that zygote get implanted then it can produce HcG and bring that thick wall back with a release of estrogen and progesterone. So is the myth false? Can you impregnate a women on her period?

A girl can only get pregnant during days 12-16 in her menstrual cycle. So you cannot get a girl pregnant if you do her during her period (gross). Your sperm can live for only 2-3 days inside the uterus, while her period lasts from 5-7 days (average). Hope this helps...

 

[nlax30]

During the Menstrual Cycle, the sudden surge of LH causes ovulation to occurs. But if the secretion of LH is inhibited by the presence of estrogen, then won't the simultaneous increase in estrogen prevent a surge of LH from happening??

No one really knows, but there are some theories. You're right though, normally estrogen will inhibit LH, but at a certain elevated level it then stimulates it. Right before ovulation the granulosa cells of the follicle also start to secrete more and more pregesterone so that could also be a trigger.

Rest assured though that you are doing pretty good in your understand of the material when you can pick up weird things like that. Also get used to reading about a mechanism or regulation pathway only to see it followed by.... "but no one knows why."

 

[nlax30]

Which now makes me curious of another question. Can you make a girl pregnant if you sleep with her while she is on her period? Although the endometrium is sloughing and the corpus luteum has atrophy, if that fertilized egg reaches the uterus it could be etopic or just implant itself somewhere (especially since not every girl is regular and you could never really know where she is on her mentrual cycle). If that zygote get implanted then it can produce HcG and bring that thick wall back with a release of estrogen and progesterone. So is the myth false? Can you impregnate a women on her period?

With the rhythm method of contraception you avoid sex ~4 days before ovulation and ~3 days afterward. The released ovum is only viable for about 24 hours after ovulation so avoiding the deed a couple days afterward is the key. Of course this is assuming a normal rhythm and that you can pinpoint when ovulation occurs. I've had some friends go this route by charting temperature throughout the cycle.

 

[PRodulous]

Can you impregnate a women on her period?

You're right that it's nearly impossible to get a girl pregnant during a certain time from of her menstrual cycle. I recall at least a couple professors saying so. However, I do believe that there is an extremely small possibility that a girl can get pregnant. For example, google search "ectopic pregnancy". It is a condition that occurs when a woman's cilia are not function properly (due to problems with microtubules and microtubule associated proteins). The egg is not passed to the uterus and implants in the fallopian tubes. I suspect that sperm can travel and fertilize the egg there. The condition is rare and the body often aborts the egg later on.

In most normal situations, any egg, fertilized or not, will not attach to the endometrium and will slough off during the menstrual cycle. Not my recommendation of birth control tho, one reason is that it's often difficult to time a girl's cycle precisely. So remember, "No Glove, no love."

 

[Zerconia2921]

During the Menstrual Cycle, the sudden surge of LH causes ovulation to occurs. But if the secretion of LH is inhibited by the presence of estrogen, then won't the simultaneous increase in estrogen prevent a surge of LH from happening??

The sudden surge of LH dosent cause ovulation to occur. FSH acts upon the follicle secreting estrogen, as the levels of estrogen increase ovulation occurs. The high level of estrogen is then lowered by LH which then induces the corpus leutem to secret progesteron and estrogen for implantaton. If the egg isnt fertilized then the levels of progesteron and estrogen decrease.

 

[tncekm]

The sudden surge of LH dosent cause ovulation to occur. FSH acts upon the follicle secreting estrogen, as the levels of estrogen increase ovulation occurs. The high level of estrogen is then lowered by LH which then induces the corpus leutem to secret progesteron and estrogen for implantaton. If the egg isnt fertilized then the levels of progesteron and estrogen decrease.

http://www.pharm.uky.edu/HomeTest/Ovulate/Ointro.html

"Ovulation is the release of a single, mature egg from an ovary. This happens once monthly about two weeks after the beginning of menstruation in the average female. Once the egg is released, it travels down the fallopian tube where it may be fertilized by sperm within twenty-four hours of release.

A sudden surge in the level of Leutenizing Hormone (LH) causes ovulation. LH is always present in the body but in smaller amounts than are seen just prior to ovulation. Around the middle of the menstrual cycle, the pituitary gland releases more LH than any other time of the cycle. The LH surge can last from 1-3 days. The beginning of the LH surge precedes ovulation by 20-44 hours which is about one and a half days. The surge in LH can usually be detected in the urine 8-12 hours after it occurs in the serum."

 

[TypeSH07]

http://www.pharm.uky.edu/HomeTest/Ovulate/Ointro.html

"Ovulation is the release of a single, mature egg from an ovary. This happens once monthly about two weeks after the beginning of menstruation in the average female. Once the egg is released, it travels down the fallopian tube where it may be fertilized by sperm within twenty-four hours of release.

A sudden surge in the level of Leutenizing Hormone (LH) causes ovulation. LH is always present in the body but in smaller amounts than are seen just prior to ovulation. Around the middle of the menstrual cycle, the pituitary gland releases more LH than any other time of the cycle. The LH surge can last from 1-3 days. The beginning of the LH surge precedes ovulation by 20-44 hours which is about one and a half days. The surge in LH can usually be detected in the urine 8-12 hours after it occurs in the serum."

Agreed. Everything I've read has the luteal surge being the cause of ovulation.

I had a reproduction question I thought I'd ask here since the topics are related. I know that the secondary oocyte won't undergo meiosis II until fertilization. Does this mean the egg and nucleus fuse before meiosis II begins or they are about to fuse??

 

[TawMus]

Fusion of the sperm and egg nucleus occurs prior to meiosis II, ootid,and ova. Once fusion has occured, the egg is now called a zygote.

 

[talkalot24]

I believe the membranes join/fuse together prior to meiosis II, and then afterwards the egg and sperm nuclei fuse.

Agreed. Everything I've read has the luteal surge being the cause of ovulation.

I had a reproduction question I thought I'd ask here since the topics are related. I know that the secondary oocyte won't undergo meiosis II until fertilization. Does this mean the egg and nucleus fuse before meiosis II begins or they are about to fuse??

 

[talkalot24]

Fusion of the sperm and egg nucleus occurs prior to meiosis II, ootid,and ova. Once fusion has occured, the egg is now called a zygote.

Are you sure? I thought the nuclei fused after the ovum was formed, thus after meiosis II ...

 

[TawMus]

Are you sure? I thought the nuclei fused after the ovum was formed, thus after meiosis II ...

sorry, I meant "after" not "prior"

 

[TypeSH07]

Are you sure? I thought the nuclei fused after the ovum was formed, thus after meiosis II ...

Yes I think that you are correct. Do you guys think menstrual cycle uterine cycle phase overlapping is important??

 

[BloodySurgeon]

Yes I think that you are correct. Do you guys think menstrual cycle uterine cycle phase overlapping is important??

What could be more important than menstrual cycle uterine cycle phase overlap?

 

[TypeSH07]

What could be more important than menstrual cycle uterine cycle phase overlap?

i don't know....

 

[Zerconia2921]

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

Correct answer is C.