How is increased muscle perfusion during exercise primarily accomplished?

• A. By constriction of capillaries within the muscles
• B. By decreased heart rate
• C. By reduced blood flow to the muscles
• D. By vasodilation of arterioles supplying the muscles

Answer: (D)

Verified step by step guidance

1. Understand the concept of muscle perfusion: Muscle perfusion refers to the delivery of blood to muscle tissues, which is essential for providing oxygen and nutrients during exercise.
2. Recognize the physiological need during exercise: During physical activity, muscles require increased oxygen and nutrients to sustain their activity. This necessitates an increase in blood flow to the active muscles.
3. Learn about vasodilation: Vasodilation is the widening of blood vessels, particularly arterioles, which increases blood flow to specific tissues. This process is regulated by signals such as nitric oxide and other vasodilatory substances released during exercise.
4. Identify the role of arterioles: Arterioles are small blood vessels that control blood flow into capillary beds. During exercise, vasodilation of arterioles supplying the muscles occurs, allowing more blood to reach the muscle tissues.
5. Eliminate incorrect options: Constriction of capillaries, decreased heart rate, and reduced blood flow to muscles would all decrease perfusion, which is counterproductive during exercise. Vasodilation of arterioles is the correct mechanism for increasing muscle perfusion.