Chapter 1. Epithelial Tissue (Part 1)

A. Introduction

Page 1

En face view of simple squamous epithelium from mesentary.

Courtesy: Professor Schwartz, Schwartz and Brecker

Epithelial tissue, or epithelium (Gr., epi, upon; thele, nipple), covers surfaces, lines spaces and is a prominent component of glands.

There are two basic forms of epithelia in the animal body.  Epithelial tissue that specifically covers surfaces or lines spaces is called epithelial membrane or barrier epithelium.  Epithelial tissue that specifically makes up the duct or secretory portions of glands is called glandular epithelium.

As a tissue that makes up membranes and glands, epithelia are designed to perform one or several of three basic functions:

  • protect underlying tissue from a host of stresses,
  • secrete substances, and
  • absorb substances.