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

Skeletal system - skull, SKULL- Present in head region. It is suppor...

SKULL- Present in head region. It is supported on the top of vertebral column. It is made up of the hardest and denest bones in the human body. It consists of cranium

What happens to the movement of molecules at equilibrium, What happens to t...

What happens to the movement of molecules at equilibrium? At equilibrium, the movement of molecules continues, but because there is no concentration gradient, there is no net m

Male reproductive disorders-preputial prolapse, Preputial prolapse Thi...

Preputial prolapse This deformity is seen in some of the tropical zebu breeds but is not uncommon in European breeds. Initially, it begins as a temperory eversion of a small p

Osmoregulation in protozoans, Osmoregulation in Protozoans Osmoregulat...

Osmoregulation in Protozoans Osmoregulation or water balance in protozoa is accomplished by contractile vacuoles. One to several contractile vacuoles may be present within the

Roles of abscisic acid, Roles of Abscisic Acid Abscisic acid (ABA) is ...

Roles of Abscisic Acid Abscisic acid (ABA) is a particularly interesting hormone with regard to the regulation of its own levels. Its levels rise and fall dramatically in seve

Explain about the essential fat in humans, Explain about the essential fat ...

Explain about the essential fat in Humans? For the body to function normally, certain amount of body fat is required. This is called essential fat. For women, average amount of

Procedures for diagnosis - immune responses and biomarkers, Demonstration o...

Demonstration of immune responses and biomarkers: This may be done either on the basis of sero-conversion study on paired sera samples or by challenge (protection) test.

State the variety of chemical and biological reactions, State the Variety o...

State the Variety of chemical and biological reactions Variety of chemical and biological reactions takes place leading to the formation of the solution phase. If we analyse th

What are the features of hnrna, Q. What are the features of hnRNA? Hete...

Q. What are the features of hnRNA? Heterogeneous nuclear RNA (hnRNA) - Primary precursor mRNA transcript made in eukaryotic nucleus are called 'hnRNA,' an abbreviation for 'het

Dietary fats required for dyslipidemia, Q. Dietary Fats required for dyslip...

Q. Dietary Fats required for dyslipidemia? Dietary Fats: There is a consistent support for the hypothesis that both the quantity and quality of fat are directly associated with

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