Question

how blood flow to a capillary in the gastrointestinal tract can be reduced.  In your answer include the terms arteriolar and sphincter.

Please provide more specific information. Like an essay

Answer 1

Vasomotor Control

Intestinal blood flow is critical for digestion, as well as being a key element of overall blood pressure control. During exercise and other environmental stresses, blood flow to the gut is restricted to allow maintenance of appropriate flows to the brain, heart, and skeletal muscles, for example. This process is regulated by the CNS via vasoconstrictor neurons with cell bodies in the para- and prevertebral sympathetic ganglia, which innervate both mesenteric blood vessels and submucosal arterioles. Vasoconstrictor neurons in prevertebral ganglia do not receive input from intestinofugal neurons, so vasoconstriction is not modulated by direct input from the gut, although pathways that run via the CNS are certainly involved.

On the other hand, there are also enteric vasodilator pathways. Submucosal vasodilator neurons have been identified by stimulation of individual neurons in ganglia and measuring dilation of nearby arterioles. These neurons are excited by cholinergic neurons in distension-activated reflex pathways running from the myenteric plexus, and act upon the blood vessels via mAChRs