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

Define autoclave - food microbiology, Define Autoclave - Food Microbiology?...

Define Autoclave - Food Microbiology? For sterilization, steam under pressure is generally employed using an instrument called autoclave. Figure illustrates the autoclave. Auto

Cow-pox (vaccinia), Epidemiology: This infection, although mostly occurrin...

Epidemiology: This infection, although mostly occurring in cows, sometimes also occurs in buffaloes. Under natural conditions, the infection takes place through inoculation by the

What is the meaning of narcolepsy, What is the meaning of Narcolepsy Th...

What is the meaning of Narcolepsy This is an inappropriate attack of sleep, the affected person has an overwhelming impulse to fall asleep or simply collapses into sleep at inc

Does ph affect the enzyme activity, Does pH affect the enzyme activity? ...

Does pH affect the enzyme activity? The concentration of hydrogen ions in solution affects the enzyme activity. Every enzyme has maximal efficiency under an optimum pH. As p

Veterinary medicine have to do with physiology, What does veterinary medici...

What does veterinary medicine have to do with physiology and biochemistry? A lot of Physiology will teach about the function of animals and their parts. This is very significan

Blunt or non-penetrating injury, Blunt or Non-penetrating Injury When ...

Blunt or Non-penetrating Injury When body is struck by a blunt object such as steering wheel or blows to chest with blunt object. External injury may appear minor but the

Aplastic anaemia, Aplastic Anaemia   Aplastic anaemia is a condition in...

Aplastic Anaemia   Aplastic anaemia is a condition in which production of red cells in the bone marrow is reduced. It involves failure to produce adequate red cells, white cell

Explain the term health, Explain the term 'health' Mention any two ways of ...

Explain the term 'health' Mention any two ways of maintaining it. Why does a doctor administer tetanus antitoxin and not a tetanus vaccine to a child Injured in a roadside acci

Vitamin - d, VITAMIN - D Also known as Calciferol / Anti ricket vit...

VITAMIN - D Also known as Calciferol / Anti ricket vitamin / sun shine vitamin. It is necessary for bones & teeth. It is synthesized in presence of UV rays of sunl

Do bacteria cells have a nucleus, Q. Do bacteria cells have a nucleus? ...

Q. Do bacteria cells have a nucleus? In bacteria the genetic material is dispersed in the cytosol and there is no inner membrane that delimits a nucleus.

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