part of part of Homo sapiens smooth muscle tissue blood vessel blood vessel smooth muscle MESH:D009131 vascular smooth muscle BTO:0001431 ZFA:0005321 smooth muscle of blood vessel UBERON:0004237 NCIT:C33853 UMLS:C1519956 vascular smooth muscle tissue CALOHA:TS-1107 blood vessel involuntary muscle non-striated muscle of blood vessel Smooth muscle found within, and composing the majority of the wall of blood vessels. involuntary muscle of blood vessel TAO:0005321 EMAPA:35177 smooth muscle tissue of blood vessel blood vessel non-striated muscle MA:0000710 Wikipedia:Vascular_smooth_muscle blood vessel smooth muscle tissue 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. UBERON:0010508