Epithelial cells are the cells that make up the skin and other sections of the body, such as the throat and the outside of internal organs. They protect the internal workings of the organs from the outside world.
Though skin may seem to be one continuous sheet covering the body, it is in fact constructed out of millions of small cells called epithelium. The cells join together to create a semi-permeable barrier that protects muscles, blood vessels and organs from dirt and other debris in the environment. Their special interconnectedness allows for the body to move while maintaining constant coverage.
The epithelial cells of the skin contain tiny hairs, called cilia, which help to further protect the body. When dirt or similar foreign materials come into contact with the skin, cilia help move the dirt away from the skin. Most epithelial cells also produce mucous as a means of protecting the body. For example, what is commonly referred to as “snot” in the nose is actually a collection of trapped debris that is captured by the nasal epithelium and prevented from entering the body. Without the epithelial cells, dust and bacteria could build up in the body, leading to diseases and infections.