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

Pollen stigma interaction - stigma, Pollen Stigma Interaction - Stigma ...

Pollen Stigma Interaction - Stigma The Stigma After landing on the stigma pollen grain germinates, and produces a pollen tube that carries the male gametes. The stigma has bee

Define the meaning of open kettles, Define the meaning of Open Kettles? ...

Define the meaning of Open Kettles? A number of foods can be satisfactorily concentrated in open kettles which are heated by steam. This is the case for jellies and jams, toma

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

Blood pressure - blood vessels, Normal 0 false false false ...

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

Steps of initiation , The entire mechanism of protein synthesis i...

The entire mechanism of protein synthesis in eukaryotes is generally the same as in prokaryotes, with three phases explained as termination, elongation and initiation. Furthermore,

How to make a 200 ml single solution, You have a 1M KCl stock solution and ...

You have a 1M KCl stock solution and a 85 mg/ml sulphuric acid stock solution. How will you make a 200 ml single solution containing 20mM KCl and 18 mg/ml sulphuric acid?

Synthesis of citratefrom acetyl coa and oxaloacetate, Synthesis of citratef...

Synthesis of citratefrom acetyl CoA and oxaloacetate: Citrate synthase catalyses this aldol condensation reaction with the release of CoA. There are certain inhibitors to  this re

What is relationship cph in photon and frequency of photon, what is relatio...

what is relationship between numbers CPH in photon and frequency of photon? Answer; the photon contains n CPH and its energy is E=hν, when photons energy increases that the num

Effects on plants of air pollutants, Effects on plants of Air pollutants ...

Effects on plants of Air pollutants SO 2 , O 3 and NO 2 are strong oxidants and can bring about significant changes in plant cell chemistry. The general effects of pollutant

What is elongation cycle , At the starting of the first round of elon...

At the starting of the first round of elongation, the initiation codon (AUG) is positioned in the P site with fMet-tRNAfMet bound to it by codon-anticodon base pairing.  In The nex

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