nbme sample q - atkal

[ArchivalUser]

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
© Increased
(D) Unchanged

please explain your answers
thanks

[ArchivalUser]

the answer is C, increased

the explanation depends on the cause of reactive hyperemia, which is accumulation of metabolic waste products e.g. adenosine, lactate, CO2 etc... During exercise the production of these waste producs increases leading to more dilatation of the local circulation. so when the clamp is removed more reactive hyperemia will be seen.

[ArchivalUser]

thanks

[ArchivalUser]

you are welcome.