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

Diagnosis and treatment of myocarditis, Diagnosis X-ray chest show...

Diagnosis X-ray chest shows cardiomegaly.  ECG shows conduction defect, low voltage QRS, atrial and ventricular disrhythrnias.  Echocardiogram - decreased LV cont

Interspecific competition and intraspecific competition, What is the distin...

What is the distinction between interspecific competition and intraspecific competition? Interspecific competition takes place among organisms of the similar species. Intras

Dormant vegetative structures, Dormant Vegetative Structures You have ...

Dormant Vegetative Structures You have learnt that light a period of chilling or application of gibberellin often breaks seed dormancy and stimulates seed germination. Vegetat

Introduction to transgenic animals, Transgenic Animal Over the centurie...

Transgenic Animal Over the centuries, animals with new combinations of genes have been produced using conventional breeding methods by means of careful selection of particular

Caracterized by progressive loss of the axonal myelin sheath, Q. What are a...

Q. What are a few diseases characterized by progressive loss of the axonal myelin sheath? Multiple sclerosis is a severe disease caused by progressive destruction of the myelin

Explain energetic function of organic molecules, What are some examples of ...

What are some examples of the energetic function of organic molecules? As they are complex molecules, presenting lots of chemical bonds, organic molecules keeps large amount of

Endocrine glands - liver, LIVE R - The liver produces a protein angiot...

LIVE R - The liver produces a protein angiotensinogen which is changed to angiotensin II by an enzyme renin secreted by the juxtaglomemlar apparatus of the nephrons in the kid

How many weeks are required to recover after blood donation, When a human d...

When a human donor gives a pint of blood, it generally requires how many weeks for body RESERVE of red corpuscles to be replaced? Is it: a) 7 week b) 3 weeks c) 1 weeks

Measurement of light intensity, Measurement of Light Intensity How do w...

Measurement of Light Intensity How do we measure the intensity of a source of light falling on a surface? You know that light spreads out uniformly in all directions from a sou

Some precautionary measures to avoid addiction, SOME PRECAUTIONARY MEASURES...

SOME PRECAUTIONARY MEASURES TO AVOID ADDICTION - DEADDICTIO N - First phase of treatment is detoxification. Next phase is of psychotherapy and counselling. Deadi

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