Now, first, let's define what the function and the purpose of the epithelial tissue is. So the epithelial tissue has three important functions. Firstly, it functions in protection. It protects the cells found underneath our epithelial layer from things like toxins, UV radiation, acidity and many other things. It acts to basically exchange the nutrients and the waste products between the cells found beneath our epithelial layer and our body cavity. And three, it basically synthesizes and secretes special types of molecules such as proteolytic, enzymes, sweat, mucus, as well as many other things.