Sfinktereihin

Sfinktereihin are muscular rings that control the opening and closing of body passages. The term "sphincter" derives from the Greek word "sphincter," meaning "to bind around" or "to constrict." These muscles are found throughout the body, playing crucial roles in regulating the flow of substances and maintaining bodily functions.

One of the most well-known sphincters is the pyloric sphincter, located at the junction of the stomach and the small intestine. It controls the passage of partially digested food from the stomach into the duodenum. Another important sphincter is the anal sphincter, which comprises both internal and external muscles and is responsible for the voluntary and involuntary control of defecation. The urethral sphincter, surrounding the urethra, regulates the release of urine.

Other sphincters include the esophageal sphincters, which prevent the reflux of stomach contents into the esophagus, and the iris sphincter muscle in the eye, which controls pupil size and regulates the amount of light entering the eye. The contraction and relaxation of these muscles are precisely regulated, allowing for controlled movement and preventing leakage. Dysfunctions of sphincters can lead to various medical conditions, such as incontinence or digestive problems.