When blood vessels constrict, what effect does it have on blood flow?

When blood vessels constrict, the internal diameter of the vessels decreases. This narrowing of the blood vessels leads to an increase in vascular resistance. As a result, while the heart may still pump blood, the overall flow of blood through the constricted vessels is reduced. Therefore, the primary effect of constriction is a decrease in blood flow to the areas supplied by those vessels. This mechanism is essential in various physiological responses, such as regulating blood pressure and redirecting blood flow during emergencies or specific bodily functions.