Introduction to histology and epithelia

Simple squamous epitheilum

Simple cuboidal epitheilum

Simple columnar epithelium

Stratified epithelium =Functions of Epithelial Tissue=

* Protection

Epithelial cells from the skin protect underlying tissue from mechanical injury, harmful chemicals, invading bacteria and from excessive loss of water. * Sensation

Sensory stimuli penetrate specialised epithelial cells. Specialised epithelial tissue containing sensory nerve endings is found in the skin, eyes, ears, nose and on the tongue. * Secretion

In glands, epithelial tissue is specialised to secrete specific chemical substances such as enzymes, hormones and lubricating fluids. * Absorption

Certain epithelial cells lining the small intestine absorb nutrients from the digestion of food. * Excretion

Epithelial tissues in the kidney excrete waste products from the body and reabsorb needed materials from the urine. Sweat is also excreted from the body by epithelial cells in the sweat glands. * Diffusion

Simple epithelium promotes the diffusion of gases, liquids and nutrients. Because they form such a thin lining, they are ideal for the diffusion of gases (eg. walls of capillaries and lungs). * Cleaning

Ciliated epithelium assists in removing dust particles and foreign bodies which have entered the air passages. The smooth, tightly-interlocking, epithelial cells that line the entire circulatory system reduce friction between the blood and the walls of the blood vessels.
 * Reduces Friction

=References=