A 22-year-old woman presents with chronic constipation. She has hard stools every 4-5 days andcomplains of incomplete evacuation. She has no other medical problems. The doctor prescribes herMiraLax.Important questions: What is the cause of constipation? What is the mechanism of action of defecation?Key objectives:1. Describe the physiology of large intestinal movement.2. Describe the pathophysiology of her symptoms.3. Know the conditions for which “laxative” can be used.4. Be able to recommend the diet and lifestyle manipulation in this case.