accounting for about 15 percent of body weight. For the average adult human, the skin has a surface area of between 1.5-2.0 square meters (16.1-21.5 sq.ft.), most of it is between 2-3 mm (0.10 inch) thick. The average square inch (6.5 cm²) of skin holds 650 sweat glands, 20 blood vessels, 60,000 melanocytes, and more than a thousand nerve endings.