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

Explain the small intestine, Explain the Small Intestine? The small int...

Explain the Small Intestine? The small intestine is made up of three sections, the duodenum, the jejunum, and the ileum. Bile from the liver and pancreatic enzymes are released

How mineral salts participate in enzymatic activity, Q. How mineral salts p...

Q. How mineral salts participate in enzymatic activity? Many mineral salts are cofactors of enzymes that are the substances without which enzymes do not work.

Amino acids, Amino acids are the subunits ( or the monomers) from which pr...

Amino acids are the subunits ( or the monomers) from which proteins (polymers) are assembled. Each amino acid comprises of an amino functional group, and a carboxyl acid group, an

Homeostasis, using a specific example describe how hormones have an importa...

using a specific example describe how hormones have an important role in the regulation of body functions and also, what happens if there is an over secretion or an under secretion

Maintenance therapy for leukemia, Maintenance Therapy A complete remis...

Maintenance Therapy A complete remission implies a clinical, haematological and bone marrow remission.  For remission therapy drugs like, methotrexate cyclophospharnide and 6-

Acute myocardial infarction with haemodynamic deterioration, Acute Myocardi...

Acute Myocardial Infarction with Haemodynamic Deterioration :  These patients may require urgent insertion of intra aortic balloon pump (IABP) followed by PTCA or surgery. 50 per

What is adaptive radiation?, What is adaptive radiation? The Adaptive r...

What is adaptive radiation? The Adaptive radiation is the appearance of several other species from one common ancestral species that have spread to various regions or environme

Write in 3-4 lines about the term belief, Q. Write in 3-4 lines about the t...

Q. Write in 3-4 lines about the term belief? Beliefs are learned by us when we were young. These include religious beliefs and beliefs about behaviour. Some beliefs lead to hea

What phenotypic ratio would be expected among the offspring, The F2 phenoty...

The F2 phenotypic ratio from a dihybrid cross with epistasis was 9:3:4. If instead of a dihybrid cross, a double heterozygote was test crossed (crossed to a homozygous recessive in

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