Which process increases blood flow to tissues by widening vessels?

Which process increases blood flow to tissues by widening vessels?

• A. Vasodilation
• B. Vasoconstriction
• C. Shock
• D. Arteriosclerosis

Answer: (A)

Vasodilation is the widening of blood vessels, especially the small arteries and arterioles, which reduces resistance and allows more blood to reach tissues. When the vessel radius increases, flow rises dramatically because flow depends strongly on radius. Local signals like nitric oxide, higher CO2, lower pH, and heat cause the smooth muscle in vessel walls to relax, expanding the lumen and delivering more oxygen and nutrients where needed. In contrast, vasoconstriction narrows vessels and reduces flow, shock involves systemic perfusion failure, and arteriosclerosis stiffens arteries and typically impedes flow rather than increasing it.

Vasodilation is the widening of blood vessels, especially the small arteries and arterioles, which reduces resistance and allows more blood to reach tissues. When the vessel radius increases, flow rises dramatically because flow depends strongly on radius. Local signals like nitric oxide, higher CO2, lower pH, and heat cause the smooth muscle in vessel walls to relax, expanding the lumen and delivering more oxygen and nutrients where needed. In contrast, vasoconstriction narrows vessels and reduces flow, shock involves systemic perfusion failure, and arteriosclerosis stiffens arteries and typically impedes flow rather than increasing it.