Physiological sphincter

Definition

A physiological sphincter is a region where the muscles constrict to control the flow of substances through an organ or duct without an anatomical sphincter structure. It functions through the coordinated action of smooth muscle or, in some cases, skeletal muscle to regulate passage, such as preventing the backflow of urine.

Related terms

Urethra: The tube that conducts urine from the bladder to outside of the body, regulated in part by physiological sphincters.

Urinary bladder: A muscular sac that stores urine until it is excreted, involving coordination with physiological sphincters for proper urine release.

Micturition: The process of urination that involves complex interactions between various physiological mechanisms including sphincter relaxation and bladder contraction