Which scenario results in constriction of arterioles & precapillary sphincters in mesenteric capillary beds?

• A. Increased metabolic activity in mesenteries.
• B. Decreased pH level near mesenteries.
• C. Low $O_2$ concentration in mesenteries.
• D. A greater need for blood elsewhere in the body.

Answer: (D)

Verified step by step guidance

1. Understand that arterioles and precapillary sphincters regulate blood flow into capillary beds by constricting or dilating.
2. Recognize that increased metabolic activity, decreased pH, and low oxygen levels typically signal a need for more blood flow to deliver oxygen and remove waste products, leading to dilation rather than constriction.
3. Consider the scenario where blood is needed elsewhere in the body, such as during exercise or in response to a fight-or-flight situation.
4. In such cases, the body prioritizes blood flow to essential organs and muscles, leading to constriction of arterioles and precapillary sphincters in less critical areas like the mesenteric capillary beds.
5. This constriction helps redirect blood to areas with a greater immediate need, ensuring efficient distribution of oxygen and nutrients throughout the body.