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 functional properties of protein hydrolysis, Explain functional pro...

Explain functional properties of protein hydrolysis Hydrolysis of food proteins using proteases (trypsin, chymootrypsin, papain and thermolysin) alters their functional propert

Causes of gerd, In addition, pregnancy or constipation may worsen GERD by i...

In addition, pregnancy or constipation may worsen GERD by increasing intra-abdominal pressure. Secondary causes of GERD include reflux caused by acid hypersecretory states, connec

What is the difference between amnion and chorion, What is the difference b...

What is the difference between amnion and chorion? Amnion is the membrane that covers the embryo. Chorion is the membrane that covers the amnion, the yolk sac and the allantois

What are sarcomeres, What are sarcomeres? Sarcomeres are the contractil...

What are sarcomeres? Sarcomeres are the contractile units of the muscle tissue formed of alternating actin blocks (thin filaments) and myosin blocks (thick filaments). Various

Define briefly about the selenium, Define briefly about the Selenium? T...

Define briefly about the Selenium? The element selenium was discovered in 1817 in association with the element sulphur. However, selenium as an essential nutrient remained unre

Medical research - conservation of wildlife, Medical Research - Conservatio...

Medical Research - Conservation of Wildlife  Many animal species are used to test drugs and vaccines and to increase our understanding of human health and disease. The nine-b

Protein digestion, Protein Digestion Enzymes that digest proteins are ...

Protein Digestion Enzymes that digest proteins are divided into two groups endopeptidases and exopeptidases according to site of their action in the protein molecule. Endopept

What are the main features of the meristematic cells, What are the main fea...

What are the main features of the meristematic cells? Why do these cells require to have a high mitotic rate? Meristematic cells have very thin cell walls, small vacuoles, a w

Plant responses to light-dark cycles, Plant Responses to Light-Dark Cycles ...

Plant Responses to Light-Dark Cycles Based on their requirement for day length (number of hours of light) for flowering plants have been grouped under three major categories,

Determine the transplantation of mitochondria, Based on your reading of the...

Based on your reading of the article "Hello Mothers, Hello Father" which of the following is a correct statement regarding the transplantation of mitochondria? A. The sperm cel

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