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 the role of lipoprotein, Explain the Role of Lipoprotein ? As d...

Explain the Role of Lipoprotein ? As discussed in the previous section, serum concentrations of Lp(a) are elevated in South Asians irrespective of their migrant status. Several

Advantages of stage two done with tissue punch, Advantages of Stage two don...

Advantages of Stage two done with tissue punch - Less traumatic to surrounding tissue - Faster progress to the impression procedure - No sutures required

Nervous system - cranial nerves, CRANIAL NERVES 12 pairs. Total weig...

CRANIAL NERVES 12 pairs. Total weight 12 gms. Upto amphibian 10 pairs cranial nerves are present. 1, 2, 8, - sensory. 3, 4, 6, 11, 12, motor. 5, 7, 9, 10 - mixed. 3

Differentiate between sterilization and disinfection, Q. Differentiate betw...

Q. Differentiate between sterilization and disinfection? Sterilization is defined as freeing the object or substance from all life of any kind. It is the process by which an ar

What are the main biological functions of water, What are the main biologic...

What are the main biological functions of water? Water is the basic solvent for chemical reactions of living beings; it is the major means of substance transportation in the ce

Are there non-parasitic viruses, Q Are there non-parasitic viruses? All...

Q Are there non-parasitic viruses? All viruses are necessitating intracellular parasites that are they depend on the host cell to complete their life cycle. A virus does not ha

Illustrate mitral stenosis and pregnancy, Q. Illustrate Mitral Stenosis and...

Q. Illustrate Mitral Stenosis and Pregnancy ? Since mitral stenosis is often seen in young women, it is not uncommon to see young women with pregnancy complicated by mitral ste

Complete test of hypothesis, Conduct a test of hypothesis to verify whether...

Conduct a test of hypothesis to verify whether a difference exists among the average numbers of ant species found at sites in the two regions of Mongolia. Use  .  You will require

What are pericardium - pleura and peritoneum, Q. What are pericardium, pleu...

Q. What are pericardium, pleura and peritoneum? Pleura are the membrane that covers the inner wall and the lungs of the chest pericardium are the membrane that covers the heart

Is the epithelium vascularized, Is the epithelium vascularized? How do nutr...

Is the epithelium vascularized? How do nutrients and oxygen reach the epithelium? Why is this feature a significant evolutionary acquisition? Epithelia are not vascularized (ca

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