Complete information on the general characters and functions of epithelial tissue

General Characters:

(1) It covers free outer and inner surface of the organs.

(2) It consists cells which are arranged in one or more layers.

(3) There has little amount of intercellular ground substances between the cells.

(4) The cells are set on non-cellular gelatinous basement membrane which is secreted by the underlying lamina propia and overlying epithelial tissue.

(5) The epitheli lacks blood vessels but they got food and O₂ through basement membrane.

Functions:

Protection, absorption, secretion and excretion are the main functions of the epithelial tissue.