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. Now, epithelial cells which constitute the epithelial tissue come in three different shapes. So we have our cuboidal, columnar and squamous. Now, cuboidal simply means that the shape of our epithelial cell is of a cube.