MEDizzy - A new mother calls the pediatrician because she is concerned

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Gastrointestinal Physiology

A new mother calls the pediatrician because she is concerned that her infant defecates after every meal. Which of the following is the cause of these normal bowel movements in newborns?

ExplanationDistention of the stomach by food initiates contraction of the rectum and often, a desire to defecate. This response is called the gastrocolic reflex, but it may be mediated by the action of gastrin on the colon rather than being neurally mediated. This response leads to defecation after meals in infants and children. In adults, defecation may be inhibited by behavioral modification. The gastroileal reflex refers to the relaxation of the cecum and passage of chyme through the ileocecal valve when food leaves the stomach. Peristaltic rushes are very intense peristaltic waves that may occur with intestinal obstruction. The intestino-intestinal reflex refers to a complete cessation of intestinal motility that may be caused by large distensions of the intestine, injury to the intestinal wall, or various intestinal bacterial infections. The defecation reflex refers to the sudden distention of the walls of the rectum produced by mass movement of fecal material into the rectum.