Vasoconstriction has which effect?

Vasoconstriction has which effect?

• A. Increases Blood Flow And Heat Transfer By Increasing Vessel Diameter.
• B. Causes Vasodilation.
• C. Lowers Blood Pressure.
• D. Reduces Blood Flow And Heat Transfer By Decreasing Diameter Of Superficial Blood Vessels.

Answer: (D)

Vasoconstriction narrows superficial blood vessels by contracting the smooth muscle in their walls, which increases resistance to blood flow. With a smaller diameter, less blood reaches the skin, so heat loss to the environment is reduced and the body conserves heat. This effect also tends to raise overall blood pressure because peripheral resistance goes up. So the described outcome—reduced blood flow and reduced heat transfer due to a smaller vessel diameter—fits vasoconstriction best. The other statements describe vasodilation, opposite effects, or lowering blood pressure, which aren’t what vasoconstriction does.

Vasoconstriction narrows superficial blood vessels by contracting the smooth muscle in their walls, which increases resistance to blood flow. With a smaller diameter, less blood reaches the skin, so heat loss to the environment is reduced and the body conserves heat. This effect also tends to raise overall blood pressure because peripheral resistance goes up. So the described outcome—reduced blood flow and reduced heat transfer due to a smaller vessel diameter—fits vasoconstriction best. The other statements describe vasodilation, opposite effects, or lowering blood pressure, which aren’t what vasoconstriction does.