The mechanism of fecal continence is a complex process, composed of a series of events, which are influenced by the consistency, volume, and speed with which the fecal material reaches the rectum; the sensitivity and distensibility of the rectum vault, and factors related to the sphincter muscles, which involve sensorial and mechanical components that require muscular and nervous integrity. The defecatory mechanism is complex and involves a sequence of events that integrates smooth and striated muscle and the central, somatic, autonomic, and enteric nervous systems. Normal defecation involves the rapid, semi-voluntary emptying of the rectum and a variable part of the colon and requires a high degree of coordination to achieve the evacuation of solid or semi-solid feces. In this chapter, the anatomical and physiological components of the anorectal portion of the gastrointestinal tract will be explained, according to their relevance to maintain continence.