The four main types of tissues in our body are (1) muscle tissue, (2) nervous tissue, (3) epithelial tissue, and (4) connective tissue.
Epithelial tissue - composed of a sheet of cells, found in different thicknesses and arrangements, cover body surfaces and cavities and they are classified according to cell shape.
Most of the epithelial tissues consist of sheets of cells that line or cover various surfaces and body cavities. However there are epithelial tissues that protect underlying tissues.
(1) The lining of our mouth, (2) inner surfaces of our digestive tract, lungs, blood vessels, bladder (3) tubules of our kidneys are examples of epithelial tissues.