part of part of surrounded by surrounded by surrounds surrounds contributes to morphology of composed primarily of uterine wall uterus smooth muscle tissue endometrium myometrium https://upload.wikimedia.org/wikipedia/commons/6/66/Illu_cervix.jpg EFO:0001970 uterine smooth muscle myometrial tunica muscularis (myometrium) uterine myometrium NCIT:C12314 BTO:0000907 The myometrium stretches (the smooth muscle cells expand in both size and number) during pregnancy to allow for the harboring of the pregnancy, and contracts in a coordinated fashion during the process of labor. After delivery the myometrium contracts to expel the placenta and reduce blood loss. tunica muscularis FMA:17743 Wikipedia:Myometrium In all mammals, the uterus develops as a specialization of the paramesonephric or Müllerian ducts, which gives rise to the infundibula, oviducts, uterus, cervix, and anterior vagina. Morphogenetic events common to development of all uteri include: 1) differentiation and growth of the myometrium, 2) differentiation and morphogenesis of the endometrial glands, and 3) organization and stratification of endometrial stroma. Uterine development is initiated in the fetus, but is only completed postnatally with differentiation and development of the endometrial glands.[well established][VHOG] MESH:D009215 The smooth muscle coat of the uterus, which forms the main mass of the organ and surrounds and supports the endometrium. VHOG:0001281 The muscular wall of the uterus. [TFD][VHOG] GAID:171 SCTID:279879004 CALOHA:TS-0652 UBERON:0001296 EMAPA:29923 UMLS:C0027088 EV:0100116 MA:0000391 serosa of uterus organ component layer reproductive structure layer of smooth muscle tissue