What is the main role of epithelial tissue?

Epithelial tissue primarily serves the function of covering and lining surfaces of the body. It forms the protective outer layer of the skin and lines various cavities, organs, and structures within the body, including the digestive tract, respiratory pathways, and blood vessels. This type of tissue acts as a barrier, providing protection against mechanical injury, pathogens, and fluid loss, while also playing significant roles in absorption, secretion, and sensation.

Epithelial cells are tightly packed, minimizing space between them, which enhances their protective capabilities. They are also involved in selective absorption and secretion, enabling the exchange of materials such as nutrients and waste in organs like the intestines and kidneys, although these are secondary roles compared to the primary function of covering and lining. This characteristic of forming continuous sheets offers an efficient system for communication and protection within the body.