Anus. The muscles of the anus are called sphincters, or in doctor terminology, sphincter complexes.
The anus is the opening at the end of the digestive tract through which waste (feces) is expelled from the body. It is controlled by a ring of muscles called the anal sphincter, which relaxes to allow feces to pass out of the body.
Skating ring
There will be a shiny ball in your feces.
sphincter
Proper rings are only formed by smooth mucle and are called sphincters. NB not all sphoncters are proper ring.
It is called a ring guard.
The Pyloric Sphincter is a ring of muscles that regulates the emptying of the stomach into the duodenum and prevents the contents of the small intestine from moving back into the stomach.
It is a whole area of volcanoes that form a "ring" around the Pacific Ocean. It doesnt form a sort of circle but they still call it a ring. Hope this helped :)
iris
The rectum is a muscular ring that is at the end of the large intestine. Its function is to keep the intestine sealed shut until the need to pass feces arises. When that need arises it assists in the moving of the feces out of the body. Hope this helpss!!!
The 9-ring
a sumo ring is called a Dohyo