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

Alcohol related emergencies, Alcohol Related Emergencies: Alcohol is o...

Alcohol Related Emergencies: Alcohol is one of  the most serious health problems. Alcoholism is defined as a primary or chronic disease with genetic, psychological and environ

Acid rain, The Phenomenon of acid rain was first introduced by Rober Angus ...

The Phenomenon of acid rain was first introduced by Rober Angus smith in 1852. Is means presence of excessive acids in rain water? Acid rain is a form of precipitation (rain, sn

Temperate rain forests - ecosystem, Temperate rain forests - Ecosystem ...

Temperate rain forests - Ecosystem The temperate rain Forests are colder than any other rain forest and exhibit a marked seasonality with regard to temperature and rainfall. R

Sources of stem cells-pulp tissue revascularization, A) General:   u...

A) General:   umbilical cord  Placenta  Bone marrow  Ophthalmic cornea { conjectiva of the eye }  Kidney  Spleen  (B) Dental:  Dental pulp

What proportion of changes in the third position, If a codon is CDC, what p...

If a codon is CDC, what proportion of nucleotide changes in the third position result in a new amino acid? If the codon is AGG, what proportion of changes in the first position res

Atp is directly requiredin which processes in muscle, ATP is DIRECTLY requi...

ATP is DIRECTLY required in which of the following processes in muscle? A. Net flux of sodium ions from intracellular space to extracellular space. B. Detachment of myosin h

Define reagents estimation of iron in the solution, Define Reagents Estimat...

Define Reagents Estimation of Iron in the Solution? 1. Conc. sulphuric acid (iron free) 2. Conc. potassium permanganate solution 3. Saturated potassium persulphate (K 2 S

Explain about the magnesium - macro minerals, Explain about the Magnesium -...

Explain about the Magnesium - macro minerals? Magnesium (Mg) ranks fourth in overall abundance in body among the cations. It is also the least abundant among macro minerals, th

What is trna structure , Transfer  RNA  (tRNA)  molecules  play  an  very s...

Transfer  RNA  (tRNA)  molecules  play  an  very significant  role  in  protein  synthesis. Each tRNA becomes covalently bonded to a particular amino acid  to  create  aminoacyl- t

State the amount of intracellular chloride, A complete motor neuron is remo...

A complete motor neuron is removed from a frog and placed in a large volume of normal physiological saline.  The neuron is healthy; it has a stable resting voltage of -70 mill

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