defecation
Defecation is the final step of digestion in which feces are expelled from the body through the anus. In humans, stool forms as the colon absorbs water and electrolytes from indigestible matter, then is stored in the rectum until a defecation reflex prompts the act. The process involves the rectum and anal canal, including two sphincters: the internal anal sphincter (involuntary) and the external anal sphincter (voluntary), as well as the pelvic floor muscles and the surrounding tissues that control anal opening.
During defecation, rectal stretch receptors trigger a reflex that relaxes the internal anal sphincter and causes
Frequency and stool form vary; normal bowel habits range roughly from three times a day to three
Common disorders include constipation (difficulty passing stool), fecal incontinence (involuntary leakage), diarrhea (loose stool), fecal impaction,