Muscle is the tissue of the body which primarily functions as a source of power. There are three types of muscle in the body. Muscle which is responsible for moving extremities and external areas of the body is called ""skeletal muscle."" Heart muscle is called ""cardiac muscle."" Muscle that is in the walls of arteries and bowel is called ""smooth muscle."",,,,,8/26/2010 17:17,,,8/26/2010 17:17,1,1,0 163,M,MUSE,"Intraurethral alprostadil, a small suppository that comes preloaded in a small applicator that is placed into the tip of the penis. The small button at the other end of the suppository is squeezed to release the suppository into the urethra. Gentle rubbing of the penis causes the suppository to dissolve, and the prostaglandin is absorbed through the urethral mucosa and passes into the corpora cavernosa to stimulate blood flow into the penis through the cAMP pathway.