TYPES of Ephitelial TISSUE

simple squamous

one layer of flat cells; alveoli of the lungs- thin to permit diffusion of gases; capillaries-thin to permit exchanges of materials; smooth to prevent abnormal blood clotting

stratified squamous

many layers of cells; surface cells flat; lower cells rounded; lower layer undergoes mitosis; epidermis-surface cells are dead; a barrier to pathogens; lining of esophagus, vagina-surface cells are living; a barrier to pathogens

transitional

many layers of cells; surface cells change from rounded to flat; lining of urinary bladder- permits expansion without tearing the lining

cuboidal

one layer of cube-shaped cells; thyroid gland-secretes thyroxine; salivary glands- secrete saliva; kidney tubules- permit reabosption of useful material back to the blood

columnar

one layer of column-shaped cells; lining of stomach- secretes gastric juice; lining of small intestine- secretes enzymes and absorbs end products of digestion (microvilli present)

ciliated

one layer of columnar cells with cilia on their free surfaces; lining of trachea- sweeps mucus and dust to the pharynx; lining of fallopian tube- sweeps ovum toward uterus