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

Hepatic portal system and the pulmonary circuit, Trace the flow of blood th...

Trace the flow of blood through the systemic circuit (hepatic portal system) and the pulmonary circuit, beginning and ending in the left ventricle .  You will be using named chamb

What is intrinsic rate of increase, In a population of e-coli, it turns int...

In a population of e-coli, it turns into 4 individuals in 1 day (assuming no deaths). What is it instantaneous per capita birth rate? Assume instantaneous death rate is 0.10. What

Absorption of lipids, Absorption of lipids Absorption of lipids is qui...

Absorption of lipids Absorption of lipids is quite different from the absorption of monosaccharides and amino acids. Figure shows the process. The free fatty acids, monoglycer

State the amount of intracellular chloride, A complete motor neuron is remo...

A complete motor neuron is removed from a frog and placed in a large volume of normal physiological saline.  The neuron is healthy; it has a stable resting voltage of -70 mill

How dietary constituents affecting the calcium absorption, How dietary cons...

How dietary constituents affecting the calcium absorption? Several dietary constituents have an effect on calcium absorption. The differences in fractional absorption from diff

Difference between fat-soluble and water-soluble vitamins, Q. What is the d...

Q. What is the difference between fat-soluble and water-soluble vitamins? Why can fat-soluble vitamins cause harm when ingested in excess? Water-soluble vitamins are those vita

Illustrate target organs of the hormones, Q. What are target organs of the ...

Q. What are target organs of the hormones? Target tissues, Target organs and target cells are those specific organs, cells and tissues upon which each hormone produces and acts

Determine st-segment elevation, Q. Determine ST-Segment Elevation? Ans...

Q. Determine ST-Segment Elevation? Ans. Exercise induced ST-segment elevation is common in subjects with post MI stress tests in leads where Q-waves are present. It has be

Illustrate the diabetic contract of the eye, Illustrate the diabetic contra...

Illustrate the diabetic contract of the eye? Diabetic Cataract: 1) Sorbitol Aldose Pathway: In patients with diabetes, there is increase in sugar alcohol which results in

Explain why goblet cells are non-functional, If for some reason our goblet ...

If for some reason our goblet cells are non-functional, this will adversely affect: 1. Production of somatostatin 2. Secretion of sebum from the sebaceous glands 3. Matura

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