IV./1.3.: Structure of the other parts of the uterine body
IV./1.3.: Structure of the other parts of the uterine body
IV./1.3.1.: Myometrium
This is the thickest layer of the uterine wall, and it consists of smooth muscle of ca. 1.3 cm thickness. This smooth muscle is composed of a meshwork of myocytes forming bundles and separated by sparse connective tissue. Three, rather poorly defined, sublayers can be distinguished, according to the main course of muscular bundles. The inner layer beneath the mucosa (stratum subvasculare) is formed mainly by bundles that are longitudinal to the axis of the uterus. Thickest of the myometrial layers, the stratum vasculare consists of circular and diagonal bundles.The outer stratum supravasculare is composed of longitudinal bundles. Owing to numerous vessels, the stratum vasculare has a spongy appearance.
The myocytes are quite large, about 50 μm in length. They can considerably (up to ten times their original length) be enlarged during pregnancy, also accompanied by the formation of new myocytes. This also involves proliferation of the connective tissue of myometrium. Following birth, the amount and size of myocytes fall back to resting levels, while the size of the uterus is diminished, nearing the value before pregnancy. The mucle layer of the cervix uteri is thinner, with more connective tissue and a sizeable amount of collagen and elastic fibers. The inner and outer layers contain networks of circular and longitudinal bundles of smooth muscle, respectively
IV./1.3.2.: Perimetrium
A serous membrane covering (tunica serosa), the perimetrium is anchored to the myometrium by subserosa, which is rich in elastic fibers and blood vessels. In the anterior, peritoneum-free part of the cervix, the outermost layer is formed by loose connective tissue (tunica adventitia).
