Pseudostratified columnar epithelium

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Pseudostratified columnar epithelium
Illustration depicting Pseudostratified ciliated columnar epithelium.
Details
Function	Epithelium
Identifiers
TH	H2.00.02.0.02021
FMA	45572
Anatomical terms of microanatomy [edit on Wikidata]

Pseudostratified columnar epithelium is a type of epithelium that, though comprising only a single layer of cells, has its cell nuclei positioned in a manner suggestive of stratified columnar epithelium. A stratified epithelium rarely occurs as squamous or cuboidal.

The term pseudostratified is derived from the appearance of this epithelium in the section which conveys the erroneous (pseudo means almost or approaching) impression that there is more than one layer of cells, when in fact this is a true simple epithelium since all the cells rest on the basement membrane. The nuclei of these cells, however, are disposed at different levels, thus creating the illusion of cellular stratification. All cells are not of equal size and not all cells extend to the luminal/apical surface; such cells are capable of cell division providing replacements for cells lost or damaged.

Pseudostratified epithelia function in secretion or absorption. If a specimen looks stratified but has cilia, then it is a pseudostratified ciliated epithelium, since stratified epithelia do not have cilia. Ciliated epithelia are more common and lines the trachea, bronchi. Non-ciliated epithelia lines the larger ducts such as the ducts of parotid glands.