GENERAL HISTOLOGY

Detailed explanation-1: -Epithelium, endothelium and mesothelium are three types of epithelial cell layers that line your internal organs, body cavities and form the outer layer of your skin. Epithelium generally lines pathways that are open to the external environment, such as your respiratory tract and digestive system.

Detailed explanation-2: -The covering or protective tissues in the animal body are epithelial tissues. Epithelium covers most organs and cavities within the body. It also forms a barrier to keep different body systems separate.

Detailed explanation-3: -Epithelial cells are a type of cell that covers the inside and outside of the surfaces of your body. They are found on your skin, blood vessels, and organs, including your urinary tract.