What are the differences between simple and stratified epithelial tissue?

Basis of differentiation 

Simple epithelial tissue

Stratified epithelial tissue

Definition 

Is the epithelium composed of a single layer of epithelial cells 

Is the epithelium composed of multiple layers of cells stacked on top of each other

Occurrence

Is found in regions where absorption, filtration, and secretion occur such as blood capillaries, heart, alveoli, and the lymphatic system

Is found in high abrasion areas that need protection such as the skin, mouth, esophagus, and vagina

Attachment to the basement membrane

All cells are bound to the basement membrane

Only the lowermost cell layers are bound to the basement membrane

Specialized types

No specialized types

2 specialized types 

1. Keratinized epithelium is composed of tough resistant proteins called keratins that make the epithelium waterproof
2. Transitional epithelium is found in tissues that are capable of stretching such those surrounding the bladder, uterus, and urethra

Protective role

Does not play a role in protection as the single layer is fragile can be damaged easily by chemical or mechanical abrasions

Plays a key role in protecting the tissues below as the multiple layers make it more robust and capable of withstanding most chemical or mechanical abrasions

Function 

Functions as a permeable membrane, permitting the movement of materials through the epithelium either through filtration or diffusion 

Stratified tissue is found where protection is important. For instance, stratified tissue can be found in the lining of the esophagus, as well as the lining of the urethra and bladder.