NEET PG / USMLE – MCQ 14

Vascular control is studied in an intact hind extremity of an anesthetized experimental animal. After a normal control period, the blood flow to the extremity is completely occluded for 1 minute. When the occlusion is released, blood flow increases abruptly and exceeds the control value for several minutes (reactive hyperemia). After an appropriate recovery period, the procedure is repeated and the extremity is actively exercised during the occlusion period. Which of the following best describes the reactive hyperemia after the second occlusion compared with that after the first occlusion?
A. Abolished
B. Decreased but not abolished
C. Increased
D. Unchanged

Correct answer : C. Increased

Accumulation of metabolites in the muscle during exercise causes vasodilation, thus increasing blood flow.

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