part_of part of smooth muscle cell uterine smooth muscle cell 2011-03-06T05:53:28Z A smooth muscle cell of the uterus. Uterine smooth muscle cells are specialized cells that make up the majority of the uterus and in particular, the myometrium. The myometrium is a thick, involuntary muscle layer, principally consisting of verticillate cell bundles that sculpt the helical architecture of the uterus. This dense muscular tissue, packed with uterine smooth muscle cells, is responsible for the significant contractile force witnessed during the physical processes of labor and childbirth. In the non-pregnant uterus, they exist in a quiescent phase. Upon implantation, these cells are primarily responsible for the expansion consequently allowing the uterus to accommodate the growing fetus. Towards the end of pregnancy, under the influence of hormonal and mechanical signals, uterine smooth muscle cells transition from a relaxed phase to an active contractile phase, culminating in the delivery of the fetus. At the cellular level, these transitions involve significant changes in the electrophysiological properties of uterine smooth muscle cells. Governed by a complex interplay of ion channels, transporters, and signaling proteins, these cells adjust their electrical activity, conduction properties, and contracting mechanisms. Any issues with these processes can result in problems such as preterm birth or labor dysfunction. (This extended description was generated by ChatGPT and reviewed by the CellGuide team, who added references, and by the CL editors, who approved it for inclusion in CL. It may contain information that applies only to some subtypes and species, and so should not be considered definitional.) uterus