Difference between Valve and Sphincter

The main difference between valve and sphincter is their structure and function. A valve contains a flap like membranous structure while a sphincter is a ring like muscular structure.

 A valve act as one-way gate allowing blood to enter the ventricles. A valve makes sure that blood exits in one direction from the ventricle. While a sphincter contracts and relaxes to regulate the movement of body fluids. When the sphincter contracts, the interior space of tube (lumen) becomes smaller and passage is closed, while when it gets relaxed, the passage opens.

Valve VS Sphincter

Here are the main differences between Valve and Sphincter

Feature	Valve	Sphincter
Structure	Flap like structure (leaflets) in hollow organs Acts like a mechanical device with moveable parts	Circular and Ring-like muscular structure
Function	Regulates one-way flow of fluids preventing backflow	Contracts and relaxes to control the flow of substances
Location	Found in the heart, veins, and certain organs	Located in various parts of the digestive and excretory systems
Control-Mechanism	Usually passive (responds automatically to pressure changes)	Active muscle contraction (to close the passage) or relaxation (to open the passage)
Examples	1. Heart valves (Mitral valve, Tricuspid valve, Aortic valve) 2. Venous valves (in veins)	1. Esophageal sphincter (controls stomach passage) 2. Anal sphincter (manages feces discharge)   3. Pyloric sphincter (between stomach and small intestine)