Sphincter (Noun)
Meaning
A ring of muscle that contracts to close an opening.
Classification
Nouns denoting body parts.
Examples
- The anal sphincter is a ring of muscle that helps control bowel movements by contracting to close the anus.
- The muscles in the iris form a sphincter that contracts to constrict the pupil in bright light.
- The urethral sphincter is a ring of muscle that contracts to close the urethra and prevent urine from flowing out.
- The pyloric sphincter is a muscular ring that contracts to close the opening between the stomach and small intestine.
- The orbicularis oculi muscle forms a sphincter around the eye that contracts to close the eyelid.