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

Define selectivity - terminologies used in chromatography, Define Selectivi...

Define Selectivity - terminologies used in chromatography? Selectivity is a measure of preference a stationary phase shows for one solute over another and is expressed as:

Define about the sporocyst larva, Define about the Sporocyst Larva? Sp...

Define about the Sporocyst Larva? Sporocyst is the second larval stage in the life cycle of F. hepatica. It develops from the miracidium larva within the pulmonary chamber of

Bergmann's method of cell plating, Bergmann's Method of Cell Plating I...

Bergmann's Method of Cell Plating In this method free cells are suspended in a liquid medium at a density twice the finally desired plating density. Melted agar containing med

Define mechanism for copper absorption, Define Mechanism for Copper Absorpt...

Define Mechanism for Copper Absorption? As in the case of other minerals, copper absorption appears to occur by two mechanisms: i) Saturable active mechanism, which operates

What is congenital heart operations and interventions, What is Congenital H...

What is Congenital Heart Operations And Interventions Aftercare of the children who have undergone cardiac procedures and surgeries is as important, and in some occasions, more

Explain requirement for simple staining of bacterial culture, Explain Requi...

Explain Requirements for Simple Staining of Bacterial Cultures Culture: 24 hours bacterial culture of E. coli and Bacillus on nutrient agar or in broth. Reagents: Methylene

Macro taxonomy, what are the character selection criteria?

what are the character selection criteria?

What proportion of the offspring, A laboratory mouse homozygous for an RFLP...

A laboratory mouse homozygous for an RFLP marker is mated to a wild mouse that is heterozygous for that marker. One of the heterozygous individuals resulting from this cross is mat

Economic development and health, Economic Development and Health The c...

Economic Development and Health The contribution of good health to improved growth and development prospects (or its opposite i.e. the contribution of poor health to reduced e

Observation of hemichordata, Q. Observation of Hemichordata ? • identif...

Q. Observation of Hemichordata ? • identify Balanoglossus as a hemicliordate and give its scientific and common name. • classify Balanogiossus LIP to the level of order.

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