Which process describes the constriction of blood vessels that restricts blood flow?

Vasoconstriction is the process that describes the narrowing or constriction of blood vessels, which results in a decrease in blood flow. This physiological response is primarily mediated by the contraction of smooth muscle in the vessel walls, particularly in arteries and arterioles. When blood vessels constrict, the resistance to blood flow increases, which can lead to elevated blood pressure and reduced blood supply to certain tissues. Vasoconstriction can occur in response to various stimuli including cold temperatures, stress, and certain hormonal signals like adrenaline.

In contrast, vasodilation is the widening of blood vessels, which increases blood flow; hypertension refers to high blood pressure rather than the constriction of vessels; and hemostasis is the process of stopping bleeding, which involves both vasoconstriction as well as clot formation. Therefore, the definition and physiological implications of vasoconstriction clearly align with the question regarding the constriction of blood vessels restricting blood flow.