Saturday, July 9, 2011

Menstruation

Menstruation is the loss of the mucous membrane of the uterus (endometrium). He appears regularly in the reproductive age women of some species of mammals. Open menstruation (where the uterus through the vagina, bleeding) is mainly in humans and close evolutionary relationships, such as chimpanzees. Although there are some differences in definitions between the sources of menstruation is usually limited to primates. Typically, in Old World monkeys and apes, including great apes and monkeys, but variably expressed in the prosimians, primates and completely absent in strepsirrhine may be weak in tarsiers. Outside of primates, it is only in bats and elephant shrew, insectivore izvestny.Samki other placental mammals have estrous cycle in which the endometrium from the animal (covert menstruation) was added at the end of their reproductive cycle. Many zoologists believe this is different from "real" menstrual cycle