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

What does ecological niche of an organism represent, What does ecological n...

What does ecological niche of an organism represent? Mention the scientific term used for modified form of reproduction in which seeds are produced without fusion of gametes.

Can you explain about thoracic aortography, Q. Can you explain about thorac...

Q. Can you explain about thoracic Aortography? Aortic arch angiography has been used to assess aortic valve or aortic root disease. Thoracic aortography is helpful for assessm

Acute and chronic tonsilitis, Acute and Chronic Tonsilitis: Tonsilitis...

Acute and Chronic Tonsilitis: Tonsilitis refers  to the inflammation of  tonsils and lymphatic tissue that are located on each side of oropharynx. Acute infection of  tonsils

How have brain-imaging methods such as pet and mri, How have brain-imaging ...

How have brain-imaging methods such as PET and MRI affected neuroscience research and clinical care? Techniques which capture pictures of the living human brain at work have be

What is the fluid that fills the nucleus called, Q. What is the fluid that ...

Q. What is the fluid that fills the nucleus called? The aqueous fluid that fills the nuclear region is called nucleoplasm or karyolymph. In the fluid there are enzymes, protein

Why is the cerebellum more developed in mammals, Why is the cerebellum more...

Why is the cerebellum more developed in mammals that jump or fly? The cerebellum is the major brain structure that coordinates the movement and the equilibrium of the body. For

Which substance does not contain hormones , Hormones are composed from seve...

Hormones are composed from several classes of molecules. As far as our present knowledge extends, hormones are not found in which of the subsequent categories of substances: a)

Complications of exchange transfusion, Complications of Exchange Transfusio...

Complications of Exchange Transfusion i) Infection of umbilical vessels and systemic injection related to blood transfusion like malaria, CMV, AIDS and hepatitis B. ii) O

Pulse wave doppler, Pulse wave  transducer has one Doppler  crystal. This c...

Pulse wave  transducer has one Doppler  crystal. This crystal emits a short burst of ultrasound at a certain frequency [PULSE REPETITION FREQUENCY (PRF)].  The ultrasqund is reflec

What is suprasternal views in echocardiography, Q. What is Suprasternal Vie...

Q. What is Suprasternal Views in echocardiography? To complete the echocardiography in the patients with CHD these views are essential. For optimal windows patient should lie

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