Columnar epithelia are epithelial cells whose heights are at least twice their width. Columnar epithelia are divided into simple, or unilayered, and stratified, or multi-layered.

Simple columnar epithelia are further divided into two categories: nonciliated and ciliated. Nonciliated columnar epithelia do not have cilia, and are found in the gastrointestinal tract and the gallbladder where they perform secretion and absorption. Ciliated columnar epithelia move mucus and other substances via cilia, and are found in the upper respiratory tract, the Fallopian tubes, the uterus, and the central part of the spinal cord.

Pseudostratified columnar epithelia are actually tightly packed simple columnar cells that appear layered. Stratified columnar epithelia have several layers, with columnar cells as the outermost of these. Stratified columnar epithelia are found in the uterus and parts of the anus and eye. The cells function in secretion and protection.

Ciliated Pseudostratified columnar epithelia are found in the lines of the trachea as well as the upper respiratory track Non-Ciliated Pseudostratified columnar epithelia are located in the lining of the male urethra.

Epithelial cells