part of part of vascular associated smooth muscle cell smooth muscle cell of the pulmonary artery 2011-03-06T05:01:28Z https://cellxgene.cziscience.com/cellguide/CL_0002591 BTO:0003336 Smooth muscle cells of the pulmonary artery form a principal component of the pulmonary artery's media layer, the middle section of the artery wall typically found between endothelial inner layer (intima) and the outermost connective tissue layer (adventitia). The unique structure of these cells, defined by fusiform shape and the absence of striations, sets them apart from other muscle cell types, including cardiac and skeletal. The primary function of smooth muscle cells of the pulmonary artery is to regulate the diameter of the pulmonary artery, which in turn controls the flow of blood into the lungs. They accomplish this task through the contraction and relaxation, indicative of vasoconstriction and vasodilation respectively. When these cells contract, the diameter of the artery narrows, leading to reduced blood flow. Conversely, relaxation of these cells widens the artery, facilitating increased blood flow. Such blood flow modulation is crucial for the maintenance of blood pressure and ensuring that the lungs receive an adequate blood supply for efficient oxygen exchange. As a result, abnormal function or proliferation of these cells can contribute to conditions such as pulmonary hypertension, a condition characterized by high blood pressure in the arteries leading to the lungs. This can occur due to hypoxia (lack of enough oxygen), leading to excessive constriction or proliferation of the smooth muscle cells. (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.) A smooth muscle of the pulmonary artery. blood vessel smooth muscle cell Homo sapiens pulmonary artery