He is working diligently on that job.

He is a diligent student, always the first to arrive in class.

The internal anal sphincter is a muscle that helps us control defecation.

The external anal sphincter plays a crucial role in helping us control defecation.

The pupillary sphincter adjusts the size of the pupil according to the intensity of light.

The vesical sphincter plays a crucial role in controlling the excretion of urine.

Dysfunction of the sphincter of Oddi is considered a type of gallstone disease.

The urethral sphincter is a muscle that controls the flow of urine.

The internal urethral sphincter plays a crucial role in controlling the flow of urine.

The anal sphincter is an important part of the body.