Types of Epithelium:

(a) Squamous epithelium : Also called pavement epithelium. 

• Cells arranged end to end like tiles on a floor.

• Cells are polygonal in surface view. 

• It forms the delicate lining of cavities (mouth, oesophagus, nose, pericardium, alveoli etc.) blood vessels and covering of the tongue and skin. 

• Epithelial cells are arranged in many layers (stratum) to prevent wear and tear in skin. This pattern is stratified squalors epithelium. 

(b) Cubical epithelium : 

• They are cube like cells that fit closely, cells look like squares in section, but free surface appears hexagonal. 

• It is found in kidney tubules, thyroid vesicles & in glands (salivary glands, sweat glands). 

• It forms germinal epithelium of gonads (testes & ovaries). 

• It involves in absorption, excretion & secretion. It also provides mechanical support.

(c) Columnar epithelium : 

• Columnar means ‘pillar-like’ epithelium. It forms lining of stomach. 

• Small intestine & colon, forming mucous membranes. 

• Border of micro villi is present at the free surface end of each cell which increases absorption efficiency in small intestine. 

(d) Ciliated epithelium : 

• Cells may be cubical or columnar. 

• On its free surface are present protoplasmic outgrowths called cilia. 

• It helps in the movement of ova in the fallopian tube.