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

Indications for surgery-aortic valve disease, Indications For Surgery :...

Indications For Surgery :  The normal aortic valve area in the adult is about 3-4 cm2. Significant symptoms occur when the valve area is seduced to 1/4"' the normal area

Define species of biological species concept, Define species according to t...

Define species according to the biological species concept. What two problems often make this definition impractical?

Define functional role of sugars in food, Define Functional Role of Sugars ...

Define Functional Role of Sugars in Food? From the consumer's point of view, sugars are basically related with sweetness. Sweetness is essentially a physiological sensation. Th

What is the mass transportation across the cell membrane, Q What is the mas...

Q What is the mass transportation across the cell membrane? Mass transportation is the exiting or the entrance of substances in or from the cell engulfed by portions of membran

Aspergillosis, Aspergillosis Aspergillosis is the most common chronic,...

Aspergillosis Aspergillosis is the most common chronic, granulomatous, necrotizing and cavitary disease of lungs, and is characterized by formation of white yellowish caseous

What are the abnormalities of gaze, What are the Abnormalities of gaze ...

What are the Abnormalities of gaze Normal gaze is when visual axes both eyes are parallel in primary gaze. when visual axes are not parallel in primary gaze, it is abnormal ga

Explain advantages of using fungi as a source of protein, Organism:-Fungi  ...

Organism:-Fungi  Advantages:- Easy to harvest from culture medium. Texture of the fungi improves the functional properties of proteins. Disdvantages:-

What is the energy source used in active transport, Q. What is the energy s...

Q. What is the energy source used in active transport through biological membranes? The energy necessary for active transport against the concentration gradient of the transpor

Explai total fertility rate and replacement level, Differentiate between To...

Differentiate between Total Fertility Rate (TFR) and Replacement Level (RL) Due to uncontrolled excessive hunting the population of tigers in a forest becomes Zero. Discuss the

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