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All epithelial tissues are found on a surface. They are distinguished from each other by their differences in cell shape and cell orientation. In all cases the cells are tightly connected. The following micrographs are available:

Squamous Cell - Cheek

Simple Columnar

Simple Squamous - top view

Stratified Squamous

Simple Squamous - side view

Pseudostratified Ciliated Columnar

Simple Cuboidal

Transitional




SIMPLE SQUAMOUS EP. - CHEEK CELLS

These cells come off the stratified squamous epithelial tissue on the inner surface of the cheek. These cells show the irregular, flat shape characteristic of typical "squamous cells." The nucleus (A) is centrally located, the cell membrane (C) is very thin, and the cell is filled with cytoplasm (B).

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SIMPLE SQUAMOUS EP.- SURFACE VIEW

This piece of frog skin allows us to observe the irregular shape of and close knit nature of the cells that make up simple squamous epithelial tissue. A - cell membrane B - nucleus, C - cytoplasm,.

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SIMPLE SQUAMOUS EP. - SIDE VIEW

At the left, simple squamous tissue (A) line the walls of blood vessels; at the right it makes up the lung alveoli (A) wall.In both cases the cells are very thin.

Locations: Capillary walls, alveoli of the lungs, covering visceral organs, lining body cavities
Function: diffusion and filtration

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SIMPLE CUBOIDAL EP.

In kidney tissue we find the kidney's tubules cut such that they appear as rings of cells around empty spaces. These cuboidal cells (A) that line these tubules are as wide as they are tall as they are deep - cuboidal. The nuclei (B) are easily observed.

Locations: lining kidney tubules, salivary ducts, pancreatic ducts

Functions: secretion, excretion, and absorption

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SIMPLE COLUMNAR EP.

The villi of the small intestine are lined by a single layer of columnar cells (A) - thus the name simple columnar epithelium. Note these cells are not as wide as they are tall with the darkly stained nuclei (B) located at the base of the cells.The cell membranes (C) are very thin but easily identified.

Locations: lining most of the digestive tract

Function: protection, secretion and absorption

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PSEUDOSTRATIFED CILIATED COLUMNAR EP.

Line A cuts through this epithelium. The columnar cells of this tissue all begin at the basement membrane; only a few reach the surface. The nuclei (C) appear at various levels giving the tissue a stratified appearance. The cilia (B) are easily seen.The mucus producing goblet cells are not visible in this micrograph.(The pseudostratified ciliated columnar epithelium you observed in the laboratory was not as "deep" as seen here and included globlet cells.)

Locations: This is a respiratory epithelium being found in such places as the nasal septum, trachea, and bronchi.

Function: trap and move "pollutants" to the mouth where they are swallowed.

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STRATIFIED SQUAMOUS EP.

The bracket labeled A marks the stratified squamous epithelium.The many layers of cells that make up this tissue are easily seen with higher magnification (right). Observe that the surface cells (at B) are flattened (are squamous). Compare this with the transitional epithelium below.

Location: mouth, vagina, esophagus, anal canal
Function: protection

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TRANSITIONAL EP.

At the left observe the ureter is lined by transitional epithelium (A). At the left the epithelium is more highly magnified. Note that the cells at the exposed surface (A) are large and rounded. They are also larger than the cells at the attached surface (B). (Compare this tissue to Stratified Squamous which has squamous cells at its exposed surface.)

Loctions: ureter, urinary bladder
Function: distention


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This page was last updated in August, 1997.

All micrographs are the property of Sherri Wick. Students of Biology 2740 and 2840 are welcome to use this page in the study and review of lecture and lab materials in the Human Physiolgoy and Anatomy courses.

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 Author: Sherri Wick, Coordinator and Instructor - Human Physiology and Anatomy Laboratories
University of Nebraska at Omaha
Allwine Hall 211E, 554-2343
swick@cwis.unomaha.edu