Human body tissues: Epithelial tissues
The epithelial tissues are formed by cells that cover the organ 
surfaces, such as the surface of skin, the airways, surfaces of soft 
organs, the reproductive tract, and the inner lining of the digestive 
tract.The cells comprising an epithelial layer are linked via semi-
permeable, tight junctions; hence, this tissue provides a barrier 
between the external environment and the organ it covers.Functions of epithelial cells 
include diffusion, filtration, secretion, selective absorption,There are three principal shapes of epithelial cell: squamous 
(scaly), columnar, and cuboidal.