What is the primary function of epithelial tissue?

Epithelial tissue primarily serves the critical function of covering surfaces and providing protection. This type of tissue forms the outer layer of skin (epidermis) and lines various cavities and organs within the body, such as the gastrointestinal tract and respiratory pathways. Epithelial cells are tightly packed together, creating a barrier that protects underlying tissues from physical damage, pathogens, and dehydration.

Additionally, this tissue type plays significant roles in absorption, secretion, and sensation, but its foundational role remains as a protective barrier. The structure of epithelial cells allows them to effectively perform these functions, as they can be organized in several formations (simple, stratified, cuboidal, columnar, etc.) depending on their location and specific function in the body.