part of part of smooth muscle tissue blood vessel blood vessel smooth muscle BTO:0001431 CALOHA:TS-1107 EMAPA:35177 MA:0000710 MESH:D009131 TAO:0005321 UBERON:0004237 UBERON:0010508 UMLS:C1519956 Vascular smooth muscle contracts or relaxes to both change the volume of blood vessels and the local blood pressure, a mechanism that is responsible for the redistribution of the blood within the body to areas where it is needed (i.e. areas with temporarily enhanced oxygen consumption). Thus the main function of vascular smooth muscle tonus is to regulate the caliber of the blood vessels in the body. Excessive vasoconstriction leads to hypertension, while excessive vasodilation as in shock leads to hypotension. ZFA:0005321 blood vessel involuntary muscle blood vessel non-striated muscle blood vessel smooth muscle tissue involuntary muscle of blood vessel non-striated muscle of blood vessel smooth muscle found within, and composing the majority of the wall of blood vessels. smooth muscle of blood vessel smooth muscle tissue of blood vessel uberon vascular smooth muscle vascular smooth muscle tissue