What is Pseudostratified Epithelial Tissue?

Pseudostratified epithelial tissue is a type of simple epithelium. It is made up of a single layer of epithelial cells that are so tightly packed together that some of the nuclei become displaced and appear at different levels. This gives the appearance of the cells being stratified, hence the name ‘pseudo-stratified’.  

Pseudostratified epithelial tissue is usually composed of columnar epithelial cells. It is rarely made up of squamous or cuboidal cells. All the cells are attached to the basement membrane. 

The pseudostratified epithelium is mostly found in regions where secretion of mucus is necessary for trapping foreign bodies. For example, it covers most of the upper respiratory tract in the respiratory system. Pseudostratified epithelial tissue is also found in regions such as the epididymis and vas deferens, where it plays combined absorptive and secretory functions.