Epithelial tissue is the covering or protective tissue in animals. It forms the outer covering like skin, outer covering of organs, inner lining of blood vessels, lungs, oesophagus, etc. It protects the body and controls the movement of materials between the body and the surroundings and between the parts of the body.
i) Squamous epithelial tissue :- This consists of a layer of thin flat cells. It is present in the linings of blood vessels, lungs, mouth, oesophagus etc.
ii) Columnar epithelial tissue :-This consists of tall pillar like cells. It is present in the walls of the intestine. Ciliated columnar epithelial tissue is found in respiratory tract.
iii) Cuboidal epithelial tissue :- This consists of cone shape cells having a basement membrane. It forms the lining of kidney, tubules and ducts of salivary glands and provide mechanical support.
iv) Glandular epithelial tissue :- This epithelial tissue folds inwards and forms a multi-cellular gland which secretes substances. This tissue is called Glandular epithelial tissue.
