Function: The functions of the sigmoid and rectum are transmitting stool toward the anus,  serving both as a collection site and with contractions, producing evacuation. Absorbing water from the stool and secreting mucus are other important functions. The parasympathetic n. stimulate contractility, secretion of mucus, and relaxation of sphincters, and the sympathetic n. produce functions antagonistic to those parasympathetic nerves.