What happens to blood flow to the extremities during vasoconstriction?

• A. It increases dramatically
• B. It is reduced and redirected toward vital organs
• C. It remains unchanged
• D. It circulates only in the upper limbs

Answer: (B)

During vasoconstriction, the sympathetic nervous system causes the smooth muscle in peripheral arteries and arterioles to contract. This tightens the vessels, increasing resistance and thereby reducing blood flow to the extremities. At the same time, the body prioritizes blood supply to essential organs like the brain and heart, redirecting more blood toward them to maintain function during stress or threat. You can think of it as shunting blood from the limbs to the core to keep vital organs well perfused.

So the blood flow to the extremities is decreased and redirected toward vital organs. It wouldn’t suddenly rise, stay the same, or be limited only to the upper limbs.