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

Coelomoducts in polyplacophora, Coelomoducts in Polyplacophora In Poly...

Coelomoducts in Polyplacophora In Polyplacophora the coelomoducts divide in the region of coelomostome and the gonadal cavities become closed off from pericardial coelom. The

Explain fermented vegetable foods, Normal 0 false false fal...

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

How temperature affect the rate of cellular respiration, How does temperatu...

How does temperature affect the rate of cellular respiration? Please explain with great detail!

Cytochemistry, Cytochemistry It is well known that certain stains and d...

Cytochemistry It is well known that certain stains and dyes specifically combine with certain chemical components of the cell. Cytochemical techniques take advantage of this fa

How is fecundation done in insects, Q. How is fecundation done in insects (...

Q. How is fecundation done in insects (internal or external)? Is there copulation between insects? Fecundation in insects is internal, with copulation.

Asexual reproduction in animals, Asexual Reproduction in Animals Repro...

Asexual Reproduction in Animals Reproduction may be referred as production of true copies. Most of the animals that are quite familiar to us generate male and female gametes (

Define iron response element and iron regulatory protein, Define Iron Respo...

Define Iron Response Element and Iron Regulatory Protein? The Iron Response Element (IRE) and the Iron Regulatory Protein (IRP) play key roles in co-ordinating regulation of ir

Population, Population was defined by Clarke in 1954. The term populat...

Population was defined by Clarke in 1954. The term population refers to the total number of individuals of a sp. occupying a particular geographic aera at a given time. A s

Are the arteries constituted of more muscle tissue, Q. Are the veins or the...

Q. Are the veins or the arteries constituted of more muscle tissue? How different are the walls of these two kinds of blood vessels? The arterial system has thicker muscle wall

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