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

Explain about left cerebral hemisphere, How is it structurally explained th...

How is it structurally explained that the motor activity of the left side of the body is controlled by the right cerebral hemisphere and the motor activity of the right side of the

Proteins of plant origin - cereal proteins, Proteins of Plant Origin - Cere...

Proteins of Plant Origin - Cereal Proteins Cereal Proteins: Cereal grains, properly ripened and dried for optimum storage stability, have protein content ranging from 6-20%.

Threshold for an action potential in neuron a, Neuron A is a healthy neuron...

Neuron A is a healthy neuron with all the usual ion channels.  When at rest with a membrane voltage of R millivolts, neuron A produces no action potentials.  The voltage thresh

Structures of a flowering plant, Which structures of a flowering plant give...

Which structures of a flowering plant give rise to (a) potatoes, (b) the fleshy scales of an onion?   (a) A potato is a tuber formed at the end of an underground stem (b) O

Ciliates - parasitic protozoan, Ciliates - Parasitic Protozoan The onl...

Ciliates - Parasitic Protozoan The only ciliate of medical and veterinary importance is Balantidium coli which inhabit the large intestine of man, apes, monkeys and pigs. B. c

What is cerumen, Q. What is cerumen? Cerumen is a fatty, oily substance...

Q. What is cerumen? Cerumen is a fatty, oily substance produced by theceruminous glands in outer part of ear canal. This compound is generally referred to as ear wax and, toget

Vitamins, VI T AMINS   Made up of protein or fat. Vitamins r...

VI T AMINS   Made up of protein or fat. Vitamins required in minute quantity for normal metabolism and body functions. Vitamins are supposed to be vital amines

Cobalt (co) - micronutrients, Cobalt (Co) - Micronutrients The Co conc...

Cobalt (Co) - Micronutrients The Co concentration in the dry matter of plants grown in soil normally lies around 0.02 to 0.5 ppm. In soils the content varies from 1 to 40 ppm.

Cracking, Cracking is the process in which large molecules are broken into ...

Cracking is the process in which large molecules are broken into smaller molecules.                      C 10 H 22         C 5 H 12 + C 5 H 10                      C 8 H

Reproduction, when pollen tube enters the embryo-sac,it has;

when pollen tube enters the embryo-sac,it has;

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