What is epithelial tissue? Give its characteristics and functions.

Epithelial tissue is the simplest animal tissue which composed of one or more layer of cells covering external and internal body organs.

Characteristics of epithelial tissue:

(i) The cells of epithelial tissue are tightly packed and form continuous sheets.

(ii) Epithelial cells have small amount of cementing material between them and almost no intercellular space.

(iii) The surface of cells may be smooth, columnar or cuboidal.

(iv) The cells of the lowermost layer rest on non-cellular basement membrane which separates it from the underlying connective tissue.

Functions: Epithelial tissue performs following functions:

(i) It protects the organs which it covers.

(ii) It absorbs water and other nutrients inside the body.

(iii) Some epithelial cells secrete ear wax, mucus and digestive juices.

(iv) It keeps different organs separate.