What structure compresses the urethra so that urine remains in the bladder?
A) Trigone
B) Internal urethral sphincter
C) Detrusor muscle
D) None of these are correct.

Question

Quizplus · Accepted Answer

Three openings at the base of the bladder, two ureters and a urethral opening, define a triangular area called the trigone. Three layers of smooth muscle make up the detrusor muscle of the bladder's walls. This muscle is very important in the physiology of passing urine. At the base of the bladder, the detrusor muscle thickens to form the internal urethral sphincter. This muscle compresses the tube leading from the bladder (the urethra) so urine remains in the bladder.

What Structure Compresses the Urethra So That Urine Remains in the Bladder