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

Biochemical function - essential elements, Biochemical Function - Essential...

Biochemical Function - Essential Elements Elements Mg, Mn, K, Ca and Fe are cofactors for many enzymatic reactions. Fe is carrier of electrons in electron transfer chain. Phos

Explain galactose metabolism, Galactose Metabolism Galactose  goes to t...

Galactose Metabolism Galactose  goes to the liver via portal blood and is phosphorylated by galactokinase togalactose-  1  -phosphate (GIP) using ATP as  a phosphate donor as s

Explain sinus venosus defect with partial anomalous venous, Explain Sinus V...

Explain Sinus Venosus Defect with Partial Anomalous Venous Connection ? In this defect the atrial septal defect is situated just below the orifice of superior vena cava above

What are the types of neurons, According to the function of the transmitted...

According to the function of the transmitted neural impulse which are the types of neurons? How different are the concepts of afference and efference of the neural impulse transmis

Closed type of circulatory systems, Closed Type of Circulatory Systems ...

Closed Type of Circulatory Systems Some non-chordates, like cephalopods (octopuses, squids), earthworms, polychactes and all vertebrates have a closed circulation along with b

Transport in plants, Osmosis and transpiration both play a part in the move...

Osmosis and transpiration both play a part in the movement of water through a plant. Which of these two processes makes the greater contribution to the movement of water up the t

Enumerate the number of converging developments, Enumerate the Number of co...

Enumerate the Number of converging developments These include: 1) A better definition of the unique developmental concepts that are applicable to infants and young children,

Limitations of ecological pyramids, Limitations of Ecological Pyramids ...

Limitations of Ecological Pyramids The pyramid of energy is a significant improvement over the previous two types of ecological pyramids, yet all of them overlook one or anot

How do taenias obtain food and make gas exchange, How do taenias obtain foo...

How do taenias obtain food and make gas exchange? Tapeworms have hooks and sucking structures on their heads (scolex) that fixate the parasite in the gut wall; these structures

Define amino acids in the building blocks of proteins, Define Amino Acids i...

Define Amino Acids in the Building Blocks of Proteins? Amino acids, as you have already illustrated, have a carboxyl group and an amino group bonded to a common carbon atom and

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