How does menstrual cycle begin, Biology

Assignment Help:

Does the hypophysis-ovaries endocrine axis work in the same way during pregnancy as in non-pregnant women? If pregnancy does not occur how does another menstrual cycle begin?

The functioning of the hypophysis is changed during pregnancy. As estrogen and progesterone levels remain elevated during the gestational period the production of GnRH (gonadotropin-releasing hormone) from the hypothalamus is inhibited. The lack of GnRH therefore inhibits the secretion of FSH and LH from the hypophysis and a new menstrual cycle does not start.

If pregnancy does not happen the lowering of estrogen and progesterone levels stimulates the production of GnRH by the hypothalamus. This hormone then hastens the adenohypophyseal secretion of FHS and LH that in their turn stimulate the maturation of follicles and the starting of a new menstrual cycle.

 


Related Discussions:- How does menstrual cycle begin

Hormones secreted by pituitary gland, (a) Hormones of the Anterior lobe - ...

(a) Hormones of the Anterior lobe - The anteriorIobe of the pituitary gland secretes the following hormones, most of them are trophic hormones. (i ) Somatotropic hormone o

What do you mean by alpha taxonomy, Q. What do you mean by Alpha Taxonomy? ...

Q. What do you mean by Alpha Taxonomy? This relates to the basic or preliminary classification based almost entirely on external morphology. This can be considered as the empir

#title.humans and environment., what are the two main pollutants that contr...

what are the two main pollutants that contribute to aci rain

Leishmaniasis, Leishmaniasis Leishmaniasis is a group of disease cause...

Leishmaniasis Leishmaniasis is a group of disease caused by protozoa of the group Leishmania, and are transmitted to man by the bite of female sandfly (Phlebotomus). Three typ

How can we increase of total peripheral resistance, How can we increase of ...

How can we increase of total peripheral resistance?   A.  A decrease in the diameter of every arteriole.   B.  An increase of sympathetic discharge to all the smooth muscles

Digestive system in the phylum arthropoda, Q. What is the kind of digestive...

Q. What is the kind of digestive system present in beings of the phylum Arthropoda? Are these animals deuterostomes or protostomes? The digestive tube of arthropods is complete

Determine the resonance frequency analysis, Resonance Frequency Analysis ...

Resonance Frequency Analysis Resonance Frequency Analysis: A non invasive device based on the principles of resonance frequency analysis (RFA) has been developed to measure pri

Under which forms is the trypanosoma cruzi found, Q. Under which forms is t...

Q. Under which forms is the Trypanosoma cruzi found in its hosts? In the definitive hosts also as in triatomine bugs (intermediate hosts) the protozoan that causes Chagas' dise

Define biocompatible material, Define each term and give an example of an a...

Define each term and give an example of an application that uses the following: a. Biocompatible material b. Biodegradable material c. Biomimetic

What is myoglobin, What is myoglobin? What is the function of this molecule...

What is myoglobin? What is the function of this molecule in the muscle tissue? Myoglobin is a pigment same to hemoglobin and present in muscle fibers. Myoglobin has a great af

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd