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

Determine the change in the amount of intracellular chloride, Determine the...

Determine the change in the amount of intracellular chloride Complete motor neuron is removed from a frog and placed in a large volume of normal physiological saline.  The neur

How do sponges try to protect themselves against harm, How do sponges try t...

How do sponges try to protect themselves against harm from the environment? Is that method efficient or rudimentary? Sponges can close their pores to avoid the entrance of wate

Explain kingdom animalia, Kingdom Animalia Multicellular, heterotrophic, ...

Kingdom Animalia Multicellular, heterotrophic, eukaryotes, tissues are specialised and most of them have organs, mostly highly responsive. Only gametes are haploid, fertilisation

Ratios of different samples of nucleic acid, Ratios of the bases in differe...

Ratios of the bases in different samples of nucleic acid yielded the following results: a.  A + C    =   0.6         b.     A  +  C    =  1            c.       A  + G    =  1.2

Which term describes a very heart/pulse rate, In studies of human body, whi...

In studies of human body, which of the below terms is used to describe a very rapid heart rate or pulse rate? Is it: a) Tachycardia b) Bradycardia c) Cardiosis d) Myoc

Describe thg epa current registration process?, How will the plant-incorpor...

How will the plant-incorporated protectants rules change EPA's current registration process? The rules clarify which plant-incorporated protectants are needed to be evaluated u

Emulsion preparation, Em u l sio n preparation Frozen deboned meat,...

Em u l sio n preparation Frozen deboned meat, fat and by-products are tempered at 0° to 4° C for 12to 15 hr and cut into pieces and coarse minced by passing through 8, 10 o

Sources of variability, Mutations and genetic recombination (in sexually re...

Mutations and genetic recombination (in sexually reproducing organisms) are major sources of variations in natural populations, In this section we will briefly mention the various

Anatomy, what is the longest cell in human body

what is the longest cell in human body

Gastropods - feeding and digestion in molluscs, Gastropods - Feeding and Di...

Gastropods - Feeding and Digestion in Molluscs In several gastropods the digestion is extracellular. Though, some herbivore gastropods like Crepidula are ciliary feeders and h

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