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

Bones, which bone forms the non-moving muscle attachment in the hip joint

which bone forms the non-moving muscle attachment in the hip joint

Types of overpopulation - consumption overpopulation, Types of overpopulati...

Types of overpopulation - Consumption overpopulation Consumption overpopulation is a phenomenon seen in technologically advanced and affluent countries such as U.S.A., Japan,

Contractile vacuoles of amoeba, Normal 0 false false false ...

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

How different is the amphibian heart from the fish heart, How different is ...

How different is the amphibian heart from the fish heart? The fish heart has only two chambers, a ventricle and an atrium, and the blood that comes to it is purely venous. I

Physiology of respiration, PHYSIOLOG Y OF RESPIRATION - 1 .      EXC...

PHYSIOLOG Y OF RESPIRATION - 1 .      EXCHANGE OF GASES - It is Haemotasis. It takes place in Alveoli between alveolar air and arterial cappilary by diffusion i.e., f

What is Ailing Implant, What is Ailing Implant Ailing Implant : An impl...

What is Ailing Implant Ailing Implant : An implant which may indicate an increased risk for failure, which can be of temporary significance or amenable to treatment and is gene

Food might become contaminated by harmful bacteria, Three ways in which foo...

Three ways in which food might become contaminated by harmful bacteria. Food may become contaminated:- (i) from the unwashed hands of a food-handler, (ii) by house- flies

How white blood cells are collectively referred, The various types of white...

The various types of white blood cells are sometime together referred to as: a) Erythrocytes (pron: eh-rith-row-cites) b) Erythroblasts (pron: eh-rith-rah-blast) c) Leuko

Are plant growth is depend on the plant harmones, Are the growth and develo...

Are the growth and development of plants only influenced by plant hormones? Chemical and Physical environmental factors, like position and intensity of light in relation to the

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