The Physiology of the Anus & Rectum

This episode reviews the physiology of the anorectum, focusing on the mechanisms of continence and defecation. We cover the anatomy and function of the internal and external anal sphincters, the puborectalis muscle, and the rectoanal inhibitory reflex. Sensory pathways, autonomic and somatic innervation, and the role of the pelvic floor are explained in detail, along with the coordination required for continence and evacuation. Clinical correlations include constipation, fecal incontinence, and functional anorectal disorders, with attention to how physiology guides surgical decision-making.