Search results
Results from the WOW.Com Content Network
The mammalian female reproductive system contains three main divisions: the vagina and uterus, which act as the receptacle for the sperm, the ovaries, which produce the female's ova, and the vulva, which mainly consists of the labia and clitoris. The vagina, uterus and ovaries are always internal while the vulva is external.
Pregnancy (mammals) A pregnant lioness. In mammals, pregnancy is the period of reproduction during which a female carries one or more live offspring from implantation in the uterus through gestation. It begins when a fertilized zygote implants in the female's uterus, and ends once it leaves the uterus.
Menstruation (mammal) Menstruation is the shedding of the uterine lining (endometrium). It occurs on a regular basis in uninseminated [1] sexually reproductive-age females of certain mammal species. Although there is some disagreement in definitions between sources, menstruation is generally considered to be limited to primates.
Sexual reproduction is the most common life cycle in multicellular eukaryotes, such as animals, fungi and plants. [6][7] Sexual reproduction also occurs in some unicellular eukaryotes. [2][8] Sexual reproduction does not occur in prokaryotes, unicellular organisms without cell nuclei, such as bacteria and archaea.
Induced ovulation occurs in some animal species that do not ovulate cyclically or spontaneously. [1][2] Ovulation can be induced by externally-derived stimuli during or before mating, such as sperm, pheromones, or mechanical stimulation during copulation. Ovulation occurs at the ovary surface and is described as the process in which an oocyte ...
Menstrual cycle The menstrual cycle is a series of natural changes in hormone production and the structures of the uterus and ovaries of the female reproductive system that makes pregnancy possible. The ovarian cycle controls the production and release of eggs and the cyclic release of estrogen and progesterone. The uterine cycle governs the preparation and maintenance of the lining of the ...
Rats are polyestrous animals that typically have rapid cycle lengths of 4 to 5 days. [22] Although they ovulate spontaneously, they do not develop a fully functioning corpus luteum unless they receive coital stimulation. Fertile mating leads to pregnancy in this way, but infertile mating leads to a state of pseudopregnancy lasting about 10 days.
This is the reproductive method used by most animal species, as opposed to viviparous animals that develop the embryos internally and metabolically dependent on the maternal circulation, until the mother gives birth to live juveniles. Ovoviviparity is a special form of oviparity where the eggs are retained inside the mother (but still ...