What is the structure of simple columnar epithelium?

Simple columnar epithelium is composed of a single layer of rectangular cells compactly arranged on the basement membrane. The individual cells are tall and narrow, giving the epithelium a column-like appearance. Each cell houses an oval-shaped nucleus, which is located near the basal surface of the cell.

Simple columnar epithelium is found in the lining of the respiratory, digestive, and reproductive systems and buccal cavity. It performs a wide range of functions including secretion, absorption, protection, transportation of nutrients in the small intestine, and providing sensory input.