The uterus
At the woman, the uterus is a hollow, odd organ, médian, assembling in the small pool (or pelvis). His form is on the whole that of a pear. It is composed of 2 parties: the collar and the body, separated by Isthmus, constriction between the corporéale hole and the endocervical channel
What the uterus is ?
External :
Ses dimensions are 8 cm by 4 cm, flattened backward and forward. The body is roughly triangular. The most later party of the body accepts the establishment of the horns of Fallope. The collar is a cylinder where is inserted the vagina (the party which projects is often called muzzle of tench). The collar has an orifice which links up the vaginal hole with the uterine hole: l ' ostium uterine. It is by this orifice that pass menstruations, and that spermatozoons go back up
Internal :
The uterine wall is made of a mucous membrane, the endomètre. This mucous membrane, hard vascular and rich in glands, varies in thickness in the course of menstrual cycle. The intermediate coat is a smooth muscle called myomètre (to unintentional order; unlike the striated muscles: in aware order). the most external party, the accidental, is covered for the most upper party by the peritoneum.
Which is the function of the uterus?
The endometer uterine (this be-with-to say the mucous membrane which papers of the interior of the uterine cavity) is sensitive to the hormones ovariennes. The first part of the cycle is devoted to the thickening of the uterine mucous membrane for a pregnancy. If there is fecundation, he egg establish in the endometer to start the pregnancy. Outwards a fecundation, the endometer is eliminated during the menstruations, which mark the beginning; a new cycle (lasted usual 28 days, but very variable a woman with an other).
In the case of pregnancy, growth of l' embryo involves the distension of the uterus. Its size will pass from 8 cm length (an orange) to 35 cm. At the time of childbirth, contractions of the uterus, intense and regular, mark the beginning of the work which will lead to the birth, the uterine collar dilates to let pass the child. Then, once the childbirth finished (baby and placenta) the uterine musculature retracts very quickly and the uterus finds its usual dimensions in a few days.
