Definition

A circular muscle that controls the opening and closing of a passage in the body.

Example

The sphincter at the end of the digestive tract helps control bowel movements.

Conversation

Did you know that the body has a muscle called the sphincter?

Really? What does it do?

It's responsible for controlling the opening and closing of certain body passages.

That’s interesting! I never realized how important that muscle is.

Synonyms & Antonyms

Root Explanation

**Sphincter** → It is derived from the Greek word "sphinkter" (σφίγξ) meaning to tighten or bind. The word refers to a muscle that constricts or closes an opening in the body.

Memory Tip

Imagine a muscle that 'tightens' or 'binds' an opening — that's what a sphincter does.

Visually Confused Words