Which of the following statements reflects the preferred method for increasing flow to a localized region such as the gut during digestion?

Which of the following statements reflects the preferred method for increasing flow to a localized region such as the gut during digestion?

• A. Elevate heart rate dramatically.
• B. Constrict systemic vessels to divert flow.
• C. Dilate vessels supplying the region.
• D. Increase stroke volume globally.

Answer: (C)

When a region like the gut needs more blood during digestion, the body lowers the resistance in the vessels supplying that area. This local vasodilation increases blood flow specifically to the gut, a process driven by metabolic signals (more CO2, H+, adenosine), nitric oxide from the endothelium, and parasympathetic activity that supports digestion. Flow to a tissue is determined by the pressure gradient and the resistance of its vessels, so reducing local resistance directly boosts that region’s flow. Raising heart rate dramatically or increasing stroke volume globally would raise overall cardiac output but doesn’t selectively increase gut flow and can redistribute blood away from the gut. Constricting systemic vessels would increase overall resistance and further decrease gut perfusion.

When a region like the gut needs more blood during digestion, the body lowers the resistance in the vessels supplying that area. This local vasodilation increases blood flow specifically to the gut, a process driven by metabolic signals (more CO2, H+, adenosine), nitric oxide from the endothelium, and parasympathetic activity that supports digestion. Flow to a tissue is determined by the pressure gradient and the resistance of its vessels, so reducing local resistance directly boosts that region’s flow.

Raising heart rate dramatically or increasing stroke volume globally would raise overall cardiac output but doesn’t selectively increase gut flow and can redistribute blood away from the gut. Constricting systemic vessels would increase overall resistance and further decrease gut perfusion.