Epithelial Tissues Overview

Study Notes

Epithelial tissues are responsible for covering and lining the body.
These tissues are composed of one or more layers of cells, arranged closely together with no space between them.
The layers are classified based on cell shape and arrangement.

Simple Squamous Epithelium:
- Single layer of flat cells.
- Forms membranes.
- Lines body cavities.
- Found in the lungs and capillaries.
Simple Cuboidal Epithelium:
- Single layer of cube-like cells.
- Common in glands and their ducts.
- Forms walls of kidney tubules.
- Covers the ovaries.
Simple Columnar Epithelium:
- Single layer of tall cells.
- Often includes goblet cells, which produce mucus.
- Lines the digestive tract to facilitate nutrient absorption.

Stratified Squamous Epithelium:
- Composed of multiple layers of flat cells.
- Provides protection and resists abrasion.
- Found in the skin, mouth, esophagus, and vagina.
- Can be keratinized (skin) or non-keratinized (mouth, esophagus).
Stratified Cuboidal Epithelium:
- Composed of more than two layers of cuboidal cells.
- Relatively rare.
- Involved in protection, secretion, and absorption.
Stratified Columnar Epithelium:
- Surface cells are columnar, with varying cell sizes and shapes beneath.
- Also relatively rare.
- Primarily functions in protection and secretion.
Transitional Epithelium:
- The shape of surface cells changes depending on the degree of stretching.
- Found in areas that need to stretch, such as the bladder, ureters, and parts of the urethra.
- Allows these organs to expand and contract without damage.