During exercise, how are skeletal muscle vessels and digestive organ vessels expected to respond?

During exercise, how are skeletal muscle vessels and digestive organ vessels expected to respond?

• A. Skeletal muscle vessels constrict; digestive organ vessels dilate
• B. Skeletal muscle vessels dilate; digestive organ vessels constrict
• C. Skeletal muscle vessels dilate; digestive organ vessels dilate
• D. Skeletal muscle vessels constrict; digestive organ vessels constrict

Answer: (B)

During exercise the body redirects blood to meet the muscles’ increased demand for oxygen and nutrients. Skeletal muscle arterioles dilate in response to local metabolic byproducts (such as adenosine, CO2, H+, and low O2), a process known as functional hyperemia, which boosts blood flow to active muscles. At the same time, the sympathetic nervous system constricts vessels to digestive organs (splanchnic circulation), reducing blood flow there to prioritize the muscles and help maintain arterial pressure. This combination—muscle vessels dilating and digestive tract vessels constricting—best describes how blood vessels respond during exercise.

During exercise the body redirects blood to meet the muscles’ increased demand for oxygen and nutrients. Skeletal muscle arterioles dilate in response to local metabolic byproducts (such as adenosine, CO2, H+, and low O2), a process known as functional hyperemia, which boosts blood flow to active muscles. At the same time, the sympathetic nervous system constricts vessels to digestive organs (splanchnic circulation), reducing blood flow there to prioritize the muscles and help maintain arterial pressure. This combination—muscle vessels dilating and digestive tract vessels constricting—best describes how blood vessels respond during exercise.