A patient visits a gastroenterologist with complaints of very moist and sometimes watery stool. The doctor conducts a physical and asks as few dietary questions but is unclear what could be the cause. He takes a stool sample from the patient and sends it off to the lab to be tested. Using what you have learned about the digestive system and in your own words, explain what part of the digestive system you think could be responsible for causing these types of bowel movements.