Which term best describes the narrowing of a vessel?

Which term best describes the narrowing of a vessel?

• A. Vasoconstriction
• B. Goniometry
• C. Vasodilation
• D. Atherosclerosis

Answer: (A)

Vessel diameter is controlled by smooth muscle tone in the vessel wall, so narrowing occurs when this smooth muscle contracts. This contraction causes a smaller lumen, increasing resistance to flow. That reversible, active tightening is called vasoconstriction. It’s a common response to sympathetic stimulation, cold, or vasoactive substances, and it helps regulate blood pressure and distribution of blood flow. Vasodilation, the opposite process, widens the vessel. Goniometry is unrelated here, since it measures joint angles. Atherosclerosis involves plaque buildup inside the arterial wall that gradually narrows the lumen over time, rather than an acute constriction from muscle tone.

Vessel diameter is controlled by smooth muscle tone in the vessel wall, so narrowing occurs when this smooth muscle contracts. This contraction causes a smaller lumen, increasing resistance to flow. That reversible, active tightening is called vasoconstriction. It’s a common response to sympathetic stimulation, cold, or vasoactive substances, and it helps regulate blood pressure and distribution of blood flow.

Vasodilation, the opposite process, widens the vessel. Goniometry is unrelated here, since it measures joint angles. Atherosclerosis involves plaque buildup inside the arterial wall that gradually narrows the lumen over time, rather than an acute constriction from muscle tone.