the location of the portion of the uterine endometrium that is shed every month is adjacent to the uterine cavity.
the location of the portion of the uterine endometrium that is shed every month is adjacent to the uterine cavity.
what is the location of the portion of the uterine endometrium that is shed every month?
adjacent to the uterine cavity
the cavity of the uterus is lined by the endometrium. this lining is composed of two layers, the functional layer (adjacent to the uterine cavity) which is shed during menstruation and an underlying basal layer (adjacent to the myometrium), which is necessary for regenerating the functional layer. trauma to the basal layer, typically after a dilation and curettage (d&c) performed after a miscarriage, or delivery, or for surgical termination of pregnancy, can lead to the development of intrauterine scars resulting in adhesions that can obliterate the cavity to varying degrees. in the extreme, the whole cavity can be scarred and occluded. even with relatively few scars, the endometrium may fail to respond to estrogen.
asherman's syndrome
l-selectin is also present on the surface of human embryo trophoblasts prior to implantation into the uterus. similar to its function in lymphocytes, l-selectin acts as a receptor to facilitate adhesion of the embryo to the site of invasion on the surface epithelium of the uterine endometrium. the embryo secretes human chorionic gonadotropin (hcg), which downregulates anti-adhesion factor, muc-1, located on the uterine epithelium at the site of invasion. removal of muc-1 exposes the oligosaccharide ligands of the uterine epithelium, thus allowing binding by the l-selectin receptor of the trophopblast cell, followed by embryo adhesion and invasion.
l-selectin