Menstrual cycle- reproduction, Biology

Assignment Help:

Menstrual Cycle- Reproduction

Menstrual cycles are characteristic of primates and do not occur in other vertebrate groups. The length of the cycle is highly variable, though 28 days is generally regarded as typical for human female. The cycle in the chimpanzee rehires about 35 days. Both estrous and menstrual cycles are regulated by the same interplay of pituitary add ovarian hormones, and the effects of the ovarian hormones on the reproductive tract are comparable in most respects. The chief differences between the two types of cycles are;

  1. The presence of a menstrual phase in primates, and
  2. The spreading of sexual receptivity throughout the cycle, rather than the limitation of it to a definite period as found in nonprimates.

During the menstrual phase the superficial layers of the endometrium are sloughed rupturing spiral arteries, resulting in bleeding. This type of bleeding does not occur in nonprimates. Spiral arteries are absent from the uteri of estrous mammals but are present in primates with the exception of the New World monkeys. New World monkey menstruate, but the of blood is greatly reduced. The menstrual phase lasting four to seven days is regarded as the beginning of the primate cycle. This arrangement is sanctioned because menstruation is the easiest period of the cycle to recognise and because it corresponds with the formation of new follicles in the ovaries. However, if the uterus alone is considered, menstruation represents the terminal event with subsidence of the corpus luteum and a consequent deficiency of ovarian hormones. The endometrium cannot maintain itself and hence regresses and the surface disintegrates.


Related Discussions:- Menstrual cycle- reproduction

Write a monovalent and divalent example, What is the positive atom referred...

What is the positive atom referred to in ionic bonds and write a monovalent and divalent example.

Name the disorder which is subject of ''the elephant man'', The name Joseph...

The name Joseph Merrick, subject of "The Elephant Man", is generally associated with one disorder, though it now seems likely he actually suffered from a different disorder. Name e

What is gene expression, What is Gene Expression ? Gene expression i...

What is Gene Expression ? Gene expression is the process by which a gene is activated to produce a certain protein. Cells are able to respond to changes in the environment i

Structure of myofibril, STRUCTUR E OF A MYOFIBRIL - The dark bands ...

STRUCTUR E OF A MYOFIBRIL - The dark bands of the myofibril are termed the A-bands (Anisotropic bands). Each A-band has at its middle a light zone called H-zone (Henson'

Respiration, #question.what are the organs of respiration in the lwer form ...

#question.what are the organs of respiration in the lwer form of animals .

Explain methods used for estimation of vitamin c, Explain Methods Used For ...

Explain Methods Used For Estimation of Vitamin C? The most commonly used methods to determine ascorbic acid in foods are: 1. Titrimetric methods - The 2, 6 dichlorophenol in

State the objectives of neuropsychological assessment, State the goals of N...

State the goals of Neuropsychological assessment Neuropsychological assessment therefore has twin goals. i) The first goal is to recognize the disrupted psychological compo

Where do the two neuronal pathways diverge, Where do the two neuronal pathw...

Where do the two neuronal pathways diverge For both the neuronal pathways i.e. light reflex and near reflex the efferent fibres go to are 3rd cranial nerve and then to sphinct

Agro industrial-cobalt, Cobalt Cobalt functions as a component of vitamin ...

Cobalt Cobalt functions as a component of vitamin B12  (cobalamin). Ruminants are not dependent on a dietary source of vitamin B12  because ruminal microorganisms can synthesize B

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