Lining all the external surfaces such as skin and internal cavities of an animal's body are covered with a continuous sheet called epithelium.
Following are the functions of epithelial tissues:
(a) It protects underlying tissues of the body.
(b) Columnar epithelial cells present in the intestine absorb the digested food.
(c) It secretes enzymes.
(d) It receives sensory stimuli.
