Epithelium is a thin, continuous, protective layer of cells that lines many internal and external surfaces of the body. Learn about the different shapes, layers and functions of epithelial cells, and see how they are classified and named. Epithelial Tissue An epithelial tissue or epithelium consists of cells arranged in continuous sheets, in either single or multiple layers. It covers body surfaces and lines hollow organs, body cavities, and ducts. It also forms glands. Types of Epithelial Tissue Functions of Epithelial Tissue : It protects the underlying tissue from friction and injury. It secret certain chemical substances that are utilized by the body. On the basal side, the epithelial cells are supported by a basement ... Epithelial tissue, also known as epithelium, is one of the basic tissue types found in animals . It forms protective sheets that cover the body’s external surfaces and lines internal cavities, organs, and glands. Epithelial tissue plays vital roles in protection, secretion, absorption, and filtration throughout the body. What is Epithelial Tissue? Epithelial tissue is one of the four primary types of tissues in the human body , alongside connective, muscle, and nervous tissues. It serves as a protective barrier and a functional interface between the internal and external environments.