Epithelial tissue is a type of tissue that forms the protective outer layer of the body and lines internal organs. It serves various functions, including protection, absorption, and secretion. For example, the skin is made up of epithelial cells that help shield the body from harmful substances and pathogens. Epithelial cells are tightly packed together, creating a barrier that prevents the entry of unwanted materials. They can be found in places like the lungs, where they help with gas exchange, and the intestines, where they assist in nutrient absorption. This tissue plays a crucial role in maintaining overall health.