Which circular muscle found in tubular structures regulates passage of substances?
A) Lumen
B) Sphincter
C) Leaflet
D) Vegetation
E) Valve

Question

Quizplus · Accepted Answer

A sphincter is a circular muscle that can constrict and relax to regulate the movement of substances through a tubular structure, such as the digestive or urinary tract. Lumen refers to the inner space of the tubular structure, leaflet is a part of a valve, and vegetation is not a relevant term in this context.

Which Circular Muscle Found in Tubular Structures Regulates Passage of Substances