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

Cellular evaluation of blood test, Cellular evaluation of blood test  F...

Cellular evaluation of blood test  Full blood count (or "complete blood count")  Hematocrit or packed cell volume (PCV) - This is the fraction of whole blood volume that con

Biosphere, Biosphere Biosphere is that part of the earth where life can...

Biosphere Biosphere is that part of the earth where life can exist. It is a narfqy layer around the surface of the earth. If you visualise the earth to be the size of an apple

Explain the advantage of internal fertilization, For animals, what is the a...

For animals, what is the advantage of internal fertilization and what type of species utilize it?

Types of growth, KINDS OF GROWTH - 1 .      AUXETIC GROWTH - Body...

KINDS OF GROWTH - 1 .      AUXETIC GROWTH - Body grows by enlargement of its cells without increase in number of cells. eg. Nematodes, rotifers, tunicates. Growth of b

Define determinants of food security - food utilization, Define Determinant...

Define Determinants of Food Security - Food Utilization? It is the proper biological use of food, requiring a diet providing sufficient energy and essential nutrients, potable

The basics of dna cloning, There  are a broad  range  of various  process  ...

There  are a broad  range  of various  process  for cloning  DNA  into  either viral  or plasmid vectors  but the basic  scheme  of events  is frequently  same.  To clone into a pl

Secretion of parathormone and calcium blood level, Q. What is the relation ...

Q. What is the relation between secretion of parathormone and the calcium blood level? The parathormone increases the calcium blood level since it stimulates the resorption (re

Define contractile protein - biological functions of protein, Define Contra...

Define Contractile Protein - biological functions of protein? These proteins take part in contractile processes like muscle proteins also those found in other cells and tissues

Congestive heart failure, In native-valve IE, acute CHF occurs more frequen...

In native-valve IE, acute CHF occurs more frequently in aortic-valve infections (29 per cent) than with mitral (20 per cent) or tricuspid disease (8 per cent). CHF may develop acut

Animal and plant cells, Animal and Plant Cells The internal structural ...

Animal and Plant Cells The internal structural organisation and information related with hereditary characters and metabolic pathways are similar in all eucaryotic cells whethe

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