Histology Virtual Lab - Epithelial Tissues

Print out the Answer Sheet before continuing.


Epithelia are tissues consisting of closely apposed cells without intervening intercellular substances. Epithelia are avascular, but all epithelia "grow" on an underlying layer of vascular connective tissue. The connective tissue and the epithelium are separated by a basement membrane. Epithelium covers all free surfaces of the body. Epithelium also lines the large internal body cavities, where it is termed mesothelium. Furthermore, the internal surfaces of blood and lymph vessels are lined by epithelium, here called endothelium.


Epithelia are classified on the basis of the number of cell layers and the shape of the cells in the surface layer.

* If there is only one layer of cells in the epithelium, it is designated simple.
* If there are two or more layers of cells, it is termed stratified.


* Cells in the surface layer are, as a rule, described according to their height as squamous (scale- or plate-like), cuboidal or columnar.

Examine each of the basic types of cells so that you get an understanding for how the layers are organized and how they are named.

Psuedostratified epithelia appears to be layered (stratified) because the cell nuclei occur in two or more levels in a row of aligned cells

View Slides - click on each of the following slides. Don't forget to sketch and label each on your answer sheet

Type of Tissue Function Location
Pseudostratified columnar removing dust and particles from airways, has cilia lines the respiratory passageways
Simple Columnar Absorption lines the uterus and most organs of the digestive tract
Simple Cuboidal Secretion and Absorption glands, kidney tubules, ovaries
Simple Squamous Diffusion and Filtration lungs, walls of capillaries and vessels
Stratified Squamous Protects underlying cells skin(keratinized) and the throat, vagina, mouth (soft)
Stratified Cuboidal Protection lines ducts of the mammary glands, sweat glands, pancreas
Stratified Columnar Protection, secretion male urethra and vas deferens, parts of the pharynx
Transitional (unstretched) Specialized to become distended urinary tract

***Once your are comfortable with the types of epithelia, move onto the QUIZ. You may use your notes and drawings.

Explore Other Histology Virtual Labs:

Virtual Histology Lab at Ohio State Medical Center - amazing "zoomify" feature for viewing online slides!

College of Medicine, University of Iowa