Theuterus orwomb is part of thereproductive system of thefemalebody. The uterus is the place a baby grows for nine months duringpregnancy. It is a pear-shapedorgan inside a woman. It is behind thebladder and in front of therectum. The uterus weighs 70 grams.[1] The endometrium is the tissue that lines the uterus. Ahormone calledestrogen makes theendometrium thick withblood and fluid. This uterine lining gives the growing baby what it needs to grow.[2] Theendometrium leaves the uterus as the monthly flow of blood (menstruation). The endometrium will form again. This happens every 28 days. The number of days can be different for each woman. The fertilized egg will move through thefallopian tube and into the uterus. It will then attach to the endometrium.
The uterus is part thefemale reproductive system. Other structures and organs that are part of the reproduction system are the vagina, ovaries and fallopian tubes.[3]
The uterus has four main parts. The fundus is the upper part of the uterus. It has a rounded shape. Another part of the uterus is the body. The uterotubal angles are the parts connected to the Fallopian tubes. The bottom part of the uterus is thecervix.[4] The uterus has three layers. The outer layer is called the perimetrium.[5] It is a thin layer that surrounds the outside of the uterus. The perimetrium is made of tissue made of epithelial cells. The middle layer is the myometrium. Most of the uterus is made up of the myometrium.[6] The layer on the inside is the endometrium. The endometrium is made of secretory, ciliated, and basal cells.[4] The uterus is not in the same place for all women. It is tilted forward in most women. Other women have a uterus that tilts up or backwards.[4][7]
The uterus is supplied byblood vessels. Blood travels to the uterus througharteries. The big arteries are the internal iliac arteries. The big arteries branch off into smaller arteries called the ovarian artery and the uterine artery. The smaller arteries give blood to all the layers of the uterus. The blood returns to the heart and lungs through theveins.[8]
The uterus is held in place by ligaments. These are the anterior, posterior, lateral, uterosacral, and roundligaments. The position of the uterus can vary depending on the contents of the bladder.[4]
The uterus changes during the life of a woman. It is inactive duringchildhood and old age. During the time that a woman or girl can have a baby it is a very active organ. It does many things. It is where menstruation begins, it is the place where the fertilizedovum attaches, it is the place where the baby grows, it is the strong muscle that pushes the baby out during birth.[6]
Cancer can form in the uterus. But this is not common. There are two types ofuterine cancer. These areendometrial cancer and uterine sarcoma. Endometrial cancer can grow from cells lining the uterus. Uterine sarcoma is a rare cancer that grows from cells in thesmooth muscle of the uterus.[9] Other tumors can grow in the uterus that are not cancer. One of these is a Uterine fibroid.[10]
A girl can be born with a uterus that is not normal. When a woman has uterus that is not normal she can also have other organs that are not normal.[11][12] She may not know this until she wants to have babies. Having a baby can be hard.[13] If a woman has a uterus that is not normal, she may not be able to have babies.[14] Many times the uterus can be corrected by surgery.[12]
The uterus changes during pregnancy. It grows with the baby. It also has fluid and theplacenta inside. It starts small but it becomes very large.[15] It can hold as much as five to twenty liters. The uterus is made of smooth muscle called the myometrium. The cells of the myometrium grow during pregnancy. Strong fibrous tissue grows on the outside of the uterus. The myometrium grows at first but becomes thinner at the end of the pregnancy. A doctor or nurse can feel the baby through the thinning uterus.[1]
The uterus can move down and be seen through the vagina. This can happen after a woman has a baby. Older women have this problem more than younger women. Other things that make women have their uterus drop down:[16]
The uterus is removed bysurgery for many reasons. Removing the uterus is called ahysterectomy.[17] Surgery to remove the uterus may need to be done after having a baby. This is because the woman may be bleeding heavily. The uterus may need to removed because there is cancer growing in it.[18]
A uterus is present when an animal gives birth to live offspring. Therefore, allmammals have a uterus exceptmonotremes. However, humans are almost alone in having a single uterus. The other mammal which has a single uterus is thechimpanzee, our nearest living relative. Other mammals have either wholly separated uteri or uteri which are fused along part of their length.
The uterus of thehorse is made of two short uterine horns. The uterus of the horse is affected by hormones.[20][21] Horses can have an infection of the uterus. The horse can also develop uterine cysts. In an older female horse, there may be scarring in the uterus after they have their baby. Damage to the uterus in the horse may make it unable to have babies.[22]
↑Nahum, G. G. (October 1998). "Uterine anomalies. How common are they, and what is their distribution among subtypes?".The Journal of Reproductive Medicine.43 (10):877–887.ISSN0024-7758.PMID9800671.
