1.General feature: (1) contain more cells and less extracellular ground substance (2) Polarisaton: ---free outer surface: face air or other things ---basal surface: face underlying CT, havebasement membrane (3) Avascularity,but innervation: ---no blood vessels ---rich in nerve terminals
---skin is the largest organ of the body, it constitutes about 16% of body weight ---its total surface area is about 1.2-2.2 m2 ---function: protection, sensory reception, excretion and thermoregulation