The uterus (from Latin "uterus", plural uteri) or womb is a major female hormone-responsive reproductive sex organ of most mammals including humans. One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, depending on the species. It is within the uterus that the fetus develops during gestation, usually developing completely in placental mammals such as humans and partially in marsupials such as kangaroos and opossums. Two uteri usually form initially in a female fetus, and in placental mammals they may partially or completely fuse into a single uterus depending on the species. In many species with two uteri, only one is functional. Humans and other higher primates such as chimpanzees, along with horses, usually have a single completely fused uterus, although in some individuals the uteri may not have completely fused. In English, the term uterus is used consistently within the medical and related professions, while the Germanic-derived term womb is more common in everyday usage.

Most animals that lay eggs, such as birds and reptiles, including most ovoviviparous species, have an oviduct instead of a uterus. Note however, that recent research into the biology of the viviparous (not merely ovoviviparous) skink Trachylepis ivensi has revealed development of a very close analogue to eutherian mammalian placental development.

In monotremes, mammals which lay eggs, namely the platypus and the echidnas, either the term uterus or oviduct is used to describe the same organ, but the egg does not develop a placenta within the mother and thus does not receive further nourishment after formation and fertilization.

Marsupials have two uteri, each of which connect to a lateral vagina and which both use a third, middle "vagina" which functions as the birth canal. Marsupial embryos form a choriovitelline "placenta" (which can be thought of as something between a monotreme egg and a "true" placenta), in which the egg's yolk sac supplies a large part of the embryo's nutrition but also attaches to the uterine wall and takes nutrients from the mother's bloodstream.

Read more about Uterus:  Function, Forms in Mammals, Anatomy, Development, Pathology, Additional Images

Other articles related to "uterus":

Transplantable Organs And Tissues - Other Organs - Uterus
... A uterine transplant is the replace an uterus which has undergone necrosis ... Though the procedure has significant potential, it has been performed only a few times ...
Uterus - Additional Images
... Schematic frontal view of female anatomy Uterus and uterine tubes Sectional plan of the gravid uterus in the third and fourth month Fetus in utero ...
Surfactant Protein A - During Parturition
... If SP-A is injected into the uterus at 15 days, mice typically deliver early ... A seemed to trigger an inflammatory response in the uterus of the mice, but later studies found an anti-inflammatory response in humans ... In fact, the level of SP-A in a human uterus typically decreases during labor ...
Begat - Anatomy - The Human Female
... The female reproductive system likewise contains two main divisions the vagina and uterus, which act as the receptacle for semen, and the ovaries, which produce the female's ova ... The vagina is attached to the uterus through the cervix, while the uterus is attached to the ovaries via the Fallopian tubes ... the ovaries release an ovum, which passes through the fallopian tube into the uterus ...
Mixed Müllerian Tumor
... MMMT and carcinosarcoma, is a malignant neoplasm found in the uterus, the ovaries, the fallopian tubes and other parts of the body that contains both carcinomatous (epithelial tissue) and sarcomatous (conne ... sarcomatous component is made of tissues found in the uterus such as endometrial, fibrous and/or smooth muscle tissues) and a heterologous type (made up of ... for between two and five percent of all tumors derived from the body of the uterus, and are found predominantly in postmenopausal women with an average age of 66 years ...