To raise blood flow selectively to the digestive system, which adjustment is more effective?

To raise blood flow selectively to the digestive system, which adjustment is more effective?

• A. Increase heart rate
• B. Narrow the vessels in the digestive tract
• C. Dilate local blood vessels in the digestive arteries
• D. Increase systemic blood volume

Answer: (C)

Focusing blood flow where it’s needed most comes down to reducing resistance in that specific vascular bed. The digestive system receives more blood when its local blood vessels dilate, which lowers resistance in the mesenteric arteries. This local vasodilation allows a greater portion of the cardiac output to pass through the gut, increasing its perfusion selectively. Increasing heart rate or increasing systemic blood volume raises overall cardiac output or arterial pressure, but they don’t preferentially boost flow to the digestive tract. In some situations, broader changes can even shunt blood away from the gut or alter distribution unfavorably. Narrowing the vessels in the digestive tract would do the opposite—reduce flow. Local vasodilation of the digestive arteries directly lowers resistance where it’s needed, making it the most effective way to raise blood flow specifically to the digestive system.

Focusing blood flow where it’s needed most comes down to reducing resistance in that specific vascular bed. The digestive system receives more blood when its local blood vessels dilate, which lowers resistance in the mesenteric arteries. This local vasodilation allows a greater portion of the cardiac output to pass through the gut, increasing its perfusion selectively.

Increasing heart rate or increasing systemic blood volume raises overall cardiac output or arterial pressure, but they don’t preferentially boost flow to the digestive tract. In some situations, broader changes can even shunt blood away from the gut or alter distribution unfavorably. Narrowing the vessels in the digestive tract would do the opposite—reduce flow.

Local vasodilation of the digestive arteries directly lowers resistance where it’s needed, making it the most effective way to raise blood flow specifically to the digestive system.