Sep 3, 2025 · Sphincters are circular-shaped muscles that open and close to control the flow of food, air, bile, pee and poop through your body. When a sphincter is relaxed, a substance can easily flow …

A sphincter is a circular muscle that normally maintains constriction of a natural body passage or orifice and relaxes as required by normal physiological functioning. Sphincters are found in many animals.

Dec 8, 2025 · Sphincters are muscles that control the flow of substances in the body. There are over 60 types of sphincters found throughout the digestive tract, urinary tract, blood vessels, and eyes. The …

Oct 10, 2024 · The internal anal sphincter is involuntary, while the external anal sphincter is under voluntary control. Together, they maintain continence and allow for controlled defecation.

Jan 6, 2026 · A sphincter is a ring-shaped muscle that surrounds and guards a natural passage or opening within the body. These muscular structures function as biological valves, regulating the flow …

sphincter muscle, any of the ringlike muscles surrounding and able to contract or close a bodily passage or opening.

By definition, sphincter muscles are responsible for controlling the body’s many openings, from those in the digestive and urinary tracts to the pupils of the eyes and in the capillaries of the cardiovascular …

Four main sphincter muscles along the alimentary canal aid in digestion: the cardiac sphincter, the pyloric sphincter, and two anal sphincters. Other sphincters are found in the iris of the eye, the bile …

Jul 2, 2025 · The sphincter muscle is a ring-like muscle that controls the opening and closing of body passages. Learn about its anatomy and functions.

Sphincters are located at various critical junctures within the digestive system, controlling the entry and exit of food material as it moves through different stages of digestion. These specialized muscles …