4 primary tissue types: epithelial tissue, connective tissue, muscle tissue, neural tissue. Simple epithelium: one layer of cells covering basal lamina. Stratified epithelium: 2 or more layers of cells above basal lamina. By shape: *always identify shape of tissue by outermost layer* Simple squamous:very thin, part of eyes, alveoli of lungs, absorption. Stratified squamous: surface of skin, were mechanical stresses are severe. Cuboidal epithelia: equal sides, appear square, nucleus is near center. Transitional: very specialized (only found in urinary system) cell has ability to stretch (always go back to original shape), urinary bladder. Columnar: a lot taller cell (nucleus is towards the base) Simple columnar epithelium: a lot of tissue has goblet cells which produce mucus, intestinal lining. Pseudostratified columnar epithelium: also has goblet cells, trachlea. Stratified columnar epithelium: rare, salivary gland duct in neck & mouth area. Secrete hormones into interstitial fluid which then goes into blood.