Structure

Location

Functions

Simple squamous epithelium (pavement epithelium)

Its composed of single layer of flat cells.

This epithelium is present in the terminal bronchioles and alveoli of the lungs, walls of Bowman's capsules and descending limb of loop of Henle.

In the blood vessels and heart it is called endothelium.

In coelom, it is called as mesothelium.

Protection, excretion gaseous exchange and secretion of coelomic fluid.

Simple cuboidal epithelium
lt is composed of short cube-shaped cells with round nuclei located in centre of the cells.

The cells of cuboidal epithelium often form microvilli on their free surface.

This epithelium is present in the small ducts of salivary glands and pancreas, thyroid vesicles, part of membranous labyrinth, proximal and distal convoluted tubules of the nephrons of kidneys, ovaries, seminiferous tubules and ciliary bodies.

Protection, secretion absorption and excretion.

Simple columnar epithelium

In this, the cells are elongated and placed side by side like column. The outer free surface of each cell is slightly broader.

This epithelium contains goblet (or mucous) cells.

It lines the stomach, intestine, gall bladder and bile duct.

It also forms the gastric glands, intestinal glands and pancreatic lobules.

Protection, secretion and absorption.

Simple ciliated epithelium

This is made of cell bearing numerous delicate hair like outgrowth, arising from basal granules.

Mucous secreting goblet cells are also present in them.

These are present in the respiratry tract and Fallopian tubes (oviducts), in Certain parts of nephrons in the kidney.

Protection as well as movement of mucus,urine, eggs and cerebrospinal fluid in particular direction with help of cilia.

Compound stratified epithelium

It has many layers of epithelial cells, the deepest layer made of cuboidal cells.

It is of four types

(i) Stratified squamous epithelium.

(i) Stratified cuboidal epithelium.

(iii) Stratified columnar epithelium.

(iv) Stratified ciliated columnar epithelium.

Occurs in the epidermis of skin of land vertebrates.

Oral cavity, tongue, pharynx, eyelids and cornea of eyes.

Covers the epiglottis, lines the larynx and upper part of palate.

lt is found on dry surfaces and are
subjected to wear and tear i.e, skin, nails.

Protects, underlying structures of body.

Compound transitional epithelium

It consists of 4 to 6 layers of cells. There is no germinative layer or basement membrane but shows mitosis. The inner most cells rest on under lying connective tissue.

It lines the larynx and Upper part of the soft palate.

It is present in renal pelvis, ureters, urinary biadder and part of the urethra.

It forms epidermis of fishes and many urodeles.

It permits distention thus, urinary bladder can be stretched considerably without being damaged.