Ileocaecal valve from the ileum, pill camera view. This valve, also called Bauhin's valve, marks the boundary between the ileum of the small intestine and the caecum, the first part of the colon of the large intestine. The small intestine is mainly responsible for absorbing nutrients from food, the colon absorbs water and passes the resulting waste to the rectum for excretion. A pill camera is a pill-sized camera that is swallowed to image the digestive tract.