Pseudostratified columnar epithelium

Pseudostratified columnar epithelium
Pseudostratified columnar epithelium
Gray964.png
Transverse section of tracheal tissue. Note that image is incorrectly labeled "ciliated stratified epithelium" at upper right.
Code TH H2.00.02.0.02021

A pseudostratified 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 epithelia. As it rarely occurs as squamous or cuboidal epithelia, it is usually considered synonymous with the term pseudostratified columnar epithelium.

The term pseudostratified is derived from the appearance of this epithelium in section which conveys the erroneous (pseudo means false) 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 basal lamina. The nuclei of these cells, however, are disposed at different levels, thus creating the illusion of cellular stratification. Not all ciliated cells extend to the luminal 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.

Three types of epithelium occur: Squamous is flattened cells. Cuboidal is cube shaped cells. Columnar consists of elongated cells. they are many layers also

Examples

  • Ciliated pseudostratified columnar epithelia are found in the lines of the trachea as well as the upper respiratory tract.
  • Non-ciliated pseudostratified columnar epithelia are located in the membranous part of male vas deferens.
  • Pseudostratified columnar epithelia with stereocilia are located in the epididymis. Stereocilia of the epididymis are not cilia. They might be better defined as giant microvilli.

Gallery

  • Types of epithelia.

  • Pseduostratified columnar ciliated epithelium lining the bronchus (Light Microscope, Hematoxylin and Eosin dye, Magnified 600 times)

External links

v · Histology: Epithelial tissue (TH H2.00.02)
Epithelial cells
Surface epithelium

Simple squamous epithelium (Endothelium, Mesothelium)

Simple cuboidal epithelium

Simple columnar epithelium

Pseudostratified columnar epithelium (Respiratory epithelium)

Stratified squamous epithelium

Stratified cuboidal epithelium

Stratified columnar epithelium

Transitional epithelium/Urothelium
Gland/
glandular epithelium
Classification
(exocrine,
endocrine)
Mechanism
Shape
Secretion
Serous glands · Mucous glands
Components
see also Template:Epithelial neoplasms

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