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

Explain the miracidium larva, Explain the Miracidium larva? Miracidium ...

Explain the Miracidium larva? Miracidium is the first stage larva that comes out from the fertilized egg. i) Miracidium is an oval, microscopic, flattened larva which appear

Dinoflagellates, Dinoflagellates are single-celled to colonial protistans ...

Dinoflagellates are single-celled to colonial protistans characterized by the two flagella, one girdling cell and the other trailing the cell. Some of the dinoflagellates exist in

Munch pressure flow model, Munch Pressure Flow Model Munch, a German p...

Munch Pressure Flow Model Munch, a German plant physiologist, proposed in 1930, a simple physical model which can be tested in the laboratory for the mechanism of phloem trans

State the goals of neuropsychological assessment, State the Goals of neurop...

State the Goals of neuropsychological assessment The psychological domains/processes/ components are mediated by specific brain structures and connected brain structures formin

Define water distribution and compartments of body water, Define Water Dist...

Define Water Distribution and Compartments of Body Water? Each one of us has a veritable 'sea within', held in place by multiple membranes and our protective envelope of skin.

Physical concepts of plant water relation - diffusion, Physical Concepts of...

Physical Concepts of Plant Water Relation - Diffusion Diffusion is a spontaneous process that leads to net movement of a substance from a region of higher concentration to a r

Explain electron volt, Explain Electron Volt Electron Volt: Amount of k...

Explain Electron Volt Electron Volt: Amount of kinetic energy obtained by an electron, initially at rest, after undergoing an acceleration by a one volt potential difference.

.micro organisms, what are the disadvantages of protozoa

what are the disadvantages of protozoa

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