Egestion

The undigested part (plant fibers) and the unabsorbed digested substances pass into the rectum. Such food remnants are temporarily stored in rectum. More water is absorbed and the remnants become semisolid to form faeces.

A special reflex called defaecation reflex causes emptying of the rectum and the faeces are passed out via the anus by the relaxation of sphincter muscle (A ring shaped muscle which contracts and relaxes to close and open the anus or anal opening).