The Physics Factbook
Edited by Glenn Elert -- Written by his students
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|Charity, Mitchell N. Your enormous surface area … A View from the Back of the Envelope. Vendian Systems.||"You've an enormous surface (~400 m2, with skin merely ~2 m2)."||2 m2|
|Bender, Arnold E. & David A. Bender. Body Surface Area. A Dictionary of Food and Nutrition. New York: Oxford University Press, 1995.||The surface area of adults is about 18,000 cm2 (men) or 16,000 cm2 (women).||1.6–1.8 m2|
|Davis, F.A. Tabler's Cyclopedic Medical Dictionary. F.A. Davis Company, 1993.||"The surface area may be calculated by multiplying 0.007184 times the weight in kilograms raised to the 0.425 power and the height in centimeters raised to the 0.725 power." [Assume a height of 5'8" (170 cm) and a mass of 150 lb (68 kg).]||1.8 m2|
|M.J. Farabee. Integumentary System. Estrella Mountain Community College, 1992-2000.||"The skin is the largest organ in the body: 12-15% of body weight, with a surface area of 1-2 [square] meters."||1–2 m2|
|Environmental Research Foundation. Dangers of Dioxin Exposures: Absorption Through the Skin. RACHEL's Hazardous Waste Newsletter. No. 120. (RACHEL = Remote Access Chemical Hazards Electronic Library.)||"In the past, the theory has been that the skin (which has a total area of 1.8 square meters in the adult human) has served as a passive barrier to chemicals."||1.8 m2|
The human body's largest organ is the skin. Skin protects body tissues against injuries and helps regulate body temperature by making the pores larger or smaller. The nerves in skin receive the stimuli that are then interpreted by the brain as touch, heat, and cold. Skin is composed of three layers: epidermis, dermis, and subcutaneous fatty tissue.
The interface between the epidermis and dermis is extremely irregular and consists of a succession of papillae, or fingerlike projections, which are smallest where the skin is thin and longest in the skin of the palms and soles. The papillae of the palms and soles are associated with elevations of the epidermis, which produce ridges that are the basis for fingerprint identification.
Subcutaneous fatty tissue is the deepest layer of the skin. It is composed of connective tissue, blood vessels, and fat cells. This layer binds the skin to underlying structures, insulates the body from cold, and stores energy in the form of fat.
The skin forms a protective barrier against the action of physical, chemical, and bacterial agents on the deeper tissues and contains the special end organs for the various sensations commonly grouped as the sense of touch. Through the activity of its sweat glands and blood vessels, it is important in maintaining body temperature. One square inch (6.5 square centimeters) of skin contains up to 4.5 m of blood vessels, which have as one of their functions the regulation of body temperature. The skin varies in thickness from 0.5 mm on the eyelids to 4 mm or more on the palms and soles.
The surface area of skin, or body surface area, can be measured in several different ways, the simplest is probably the Mosteller formula.
|Haycock, Schwartz, Wisotsky (1978)||0.024265 · height[cm]0.3964 · weight[kg]0.5378|
|Gehan & George (1970)||0.0235 · height[cm]0.42246 · weight[kg]0.51456|
|Boyd (1935)||0.0003207 · height[cm]0.3 · weight[g](0.7285 – 0.0188 · log(weight[g]))|
|DuBois & DuBois (1916)||0.20247 · height[m]0.725 · weight[kg]0.425|
(children from 3 to 30 kg)
The measurement of the surface area is commonly used by doctors to calculate drug dosages, ventilation, fluid requirements, and extracorporeal circulation.
Igor Fridman -- 2001
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