Defecation involves the [[1]] of the anal sphincter muscles and the [[2]] of the rectal muscles, which push the feces out of the body. 

Defecation involves the relaxation of the anal sphincter muscles and the contraction of the rectal muscles, which pushes the feces out of the body. 

Defecation is the final stage in the process of digestion, where undigested waste material is eliminated through the anus in the form of feces. Rectum distended with feces triggers a reflex called the defecation reflex.

The defecation reflex involves the relaxation of the internal anal sphincter and the contraction of the rectal muscles. This allows the feces to move toward the anal canal. The external anal sphincter, which is under voluntary control, must also relax for the feces to be eliminated from the body.