Simple columnar epithelium is a type of tissue made up of a single layer of tall, column-shaped cells. This epithelium is primarily found in areas of the body where absorption and secretion occur, such as the lining of the gastrointestinal tract and the uterus. The cells often contain microvilli, which increase surface area for better absorption. In addition to absorption, simple columnar epithelium may also have goblet cells that produce mucus. This mucus helps to protect and lubricate the surfaces of organs. Overall, simple columnar epithelium plays a crucial role in maintaining the function of various organs in the body.