Functional Components

There are three functional components of the lower urinary tract. They are arranged in series (with a gap at the level of the male prostatic urethra). Their functional roles are determined ultimately by their innervation:
      • detrusor muscle (which expels urine) = smooth muscle coat of the bladder apex & body;
      • smooth muscle sphincter (internal urethral sphincter) = the muscle coat of the bladder neck and cranial urethra; and
      • striated urethral sphincter (external urethral sphincter) = urethralis muscle which encircles the caudal urethra.

Go Top