pseudostratifikált

Pseudostratified is a term used in biology, specifically in histology, to describe a type of epithelial tissue. This tissue appears to have multiple layers of cells, but upon closer examination, it is found that all cells are in contact with the basement membrane, even though their nuclei are at different levels. This gives the false impression of stratification, hence the prefix "pseudo" meaning false.

Commonly, pseudostratified epithelium is a simple epithelium, meaning it consists of only one layer of cells. However, its appearance can be misleading due to the arrangement of the cell nuclei. The cells typically vary in height, with some being tall and columnar while others are shorter. This variation in height, along with the irregularly positioned nuclei, creates the illusion of a stratified (layered) tissue.

Pseudostratified epithelium is often ciliated, meaning it has hair-like projections called cilia on its apical surface. These cilia beat in a coordinated manner to move substances along the surface of the epithelium. For example, pseudostratified columnar ciliated epithelium lines the airways of the respiratory tract, where the cilia help to move mucus and trapped particles away from the lungs. Another common type is pseudostratified columnar epithelium with stereocilia, found in the male reproductive tract, where stereocilia are non-motile, long microvilli that increase surface area for absorption.