Skin Components
See also: Skin layersSkin has mesodermal cells, pigmentation, or melanin provided by melanocytes, which absorb some of the potentially dangerous ultraviolet radiation (UV) in sunlight. It also contains DNA-repair enzymes that help reverse UV damage, and people who lack the genes for these enzymes suffer high rates of skin cancer. One form predominantly produced by UV light, malignant melanoma, is particularly invasive, causing it to spread quickly, and can often be deadly. Human skin pigmentation varies among populations in a striking manner. This has led to the classification of people(s) on the basis of skin color.
The skin is the largest organ in the human body. For the average adult human, the skin has a surface area of between 1.5-2.0 square metres (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 1,000 nerve endings.
Read more about this topic: Human Skin
Famous quotes containing the words skin and/or components:
“... the trouble is that most people in this country think that we can stay out of wars in other parts of the world. Even if we stay out of it and save our own skins, we cannot escape the conditions which will undoubtedly exist in other parts of the world and which will react against us.... We are all of us selfish ... and if we can save our own skins, the rest of the world can go. The best we can do is to realize nobody can save his own skin alone. We must all hang together.”
—Eleanor Roosevelt (1884–1962)
“Hence, a generative grammar must be a system of rules that can iterate to generate an indefinitely large number of structures. This system of rules can be analyzed into the three major components of a generative grammar: the syntactic, phonological, and semantic components.”
—Noam Chomsky (b. 1928)