Which term means decrease in diameter of blood vessels?

Which term means decrease in diameter of blood vessels?

• A. Vasodilation
• B. Hypertension
• C. Tachycardia
• D. Vasoconstriction

Answer: (D)

Decreasing the diameter of blood vessels is vasoconstriction. It happens when the smooth muscle in the vessel walls, especially in arterioles, contracts and narrows the lumen. That narrowing increases vascular resistance, which can raise arterial pressure and redirect blood flow toward essential organs when needed. It’s the opposite of vasodilation, where the vessels widen to allow more flow and lower resistance. The term hypertension describes high blood pressure, not a direct diameter change; tachycardia is a fast heart rate, and does not specify changes in vessel diameter.

Decreasing the diameter of blood vessels is vasoconstriction. It happens when the smooth muscle in the vessel walls, especially in arterioles, contracts and narrows the lumen. That narrowing increases vascular resistance, which can raise arterial pressure and redirect blood flow toward essential organs when needed. It’s the opposite of vasodilation, where the vessels widen to allow more flow and lower resistance. The term hypertension describes high blood pressure, not a direct diameter change; tachycardia is a fast heart rate, and does not specify changes in vessel diameter.