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

Physical signs of mitral regurgitation, Q. Physical Signs of mitral regurgi...

Q. Physical Signs of mitral regurgitation? Pulse is of normal character but carotid upstroke may be brisk. Atrial fibrillation is often present in a patient with advanced disea

Why epiphyseal closure differs between males and females, It is said during...

It is said during puberty rising sex hormones stimulate osteoblasts to produce bone faster than the rate at which epiphyseal cartilage expands. The timing of epiphyseal closure dif

Explain about ia muscle-spindle, Which of the following occur in response t...

Which of the following occur in response to an increase in the length of the right knee extensors in response to a quick tap applied to the right patellar tendon?  An increase in t

Define the control of tear production, Define the control of tear productio...

Define the control of tear production. Control of Tear Production The lacrimal secretary system was initially thought to be comprised of two parts, basic secretors and r

Cloning, Cloning Cloning is the procedure of creating an identical copy...

Cloning Cloning is the procedure of creating an identical copy of something. It together refers to procedures used to form copies of DNA fragments (molecular cloning), cells (c

What kind of sounds produced by a collapsed lung, The nature of the sounds ...

The nature of the sounds produced by percussion (tapping) a patient's chest can tell a physician a great deal about the condition of the organs within the thoracic cavity. Healthy,

Body fluids of marine teleost, Body Fluids of Marine Teleost The body ...

Body Fluids of Marine Teleost The body fluids of marine teleost are hypotonic to seawater, so these fishes lose water to the environment especially across the gill epithelium.

Functions of endosperm, Functions of Endosperm The tissue of young en...

Functions of Endosperm The tissue of young endosperm is rich in food materials and various growth hormones. It regulates the precise mode of embryo development and nourishes

Supportive evidence - erythema marginatum, Minor Criteria These are arth...

Minor Criteria These are arthralgia, fever, prolonged PR interval, raised ESR and C-reactive protein levels. In some cases abdominal pain and epistaxis may occur. Other non spec

Define the methods of concentration, Define the Methods of Concentration? ...

Define the Methods of Concentration? We define the concentration process as one that starts with a liquid product and ends up with a more concentrated, although still liquid a

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