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

Vascular tissues, VASCULA R TISSUES (= FLUID TISSUES) - The vascula...

VASCULA R TISSUES (= FLUID TISSUES) - The vascular tissues are of two types: blood and lymph.

Effects of cardiogenic pulmonary edema, Effects of Cardiogenic Pulmonary Ed...

Effects of Cardiogenic Pulmonary Edema Interference with oxygen transfer in the lungs Depression arterial oxygen tension Sense of suffocation and oppression in the

Types of endoplasmic reticulum, TYPES E.R. consists of two types -     ...

TYPES E.R. consists of two types -        1. Rough E.R.                2. Smooth E.R.   R o ugh E.R.   S m o o th E.R.

Vitamin - k, VITAMIN - K Also known as naptho quionone / anti haemo...

VITAMIN - K Also known as naptho quionone / anti haemorrhagic vitamin / coagulation vitamin / menadone . It requires for formation of blood clotting factor prothrombin.

Seed germination - development of plant, Seed Germination - Development of ...

Seed Germination - Development of plant The environmental factors that influence the germination of seeds are: Water availability, Optimal light, Aeratio

Which functional group ionization is stabilized by resonance, In which of t...

In which of the following functional groups ionization is stabilized by resonance? Select one: a. Carboxyl b. Hydroxyl c. Amine d. Aldehyde e. All of the above

What is calvin cycle, What is Calvin Cycle? The dark reactions of photo...

What is Calvin Cycle? The dark reactions of photosynthesis are also known as the Calvin cycle. This process synthesizes glucose molecules using carbon dioxide from the atmosphe

How enzyme to cut two pieces of dna, Critical Thinking Why is it necessary ...

Critical Thinking Why is it necessary to use the same restriction enzyme to cut two pieces of DNA that are to be joined together? As each restriction enzyme recognizes a specif

Define the sun and solar drying method, Define the Sun and Solar Drying Met...

Define the Sun and Solar Drying Method? The make use of solar energy to preserve the food items is mainly the oldest form of food reservation and is still practiced today for f

Explain Stirred-tank bioreactors, Normal 0 false false fals...

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

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