Skin Facts

The skin is the largest organ of the body. On the average person, the skin is approximately 3000 square inches and weighs approximately seven pounds. While the eyes are the â€Å"windows of the soul†, the skin is the â€Å"window to the body† because it is the only organ that can be seen. The skin contains 25% of the body’s blood supply, which flow completely through the skin once every minute. The skin is the body’s largest organ of immunity. It is the body’s first line of defence, the boundary where self is designed from non-self, yet it is highly interactive with the environment. Anatomy of Normal Skin Approximately 50% of the body’s primary cells of immunity are housed in the skin at any minute. After puberty, these cells are matured in the skin. The skin is biodynamic, alive up to the stratum corneum the only barrier the skin has to the outside world. The stratum corneum is less than the thickness of one human hair. In one square inch of the skin there are 2800 openings for sweat and oil glands. Over three million sweat glands cover the body, contributing to one of the skin’s many nicknames, the third kidney. In one day, skin will release one to several millilitres’ of water. As we get older, these sweat glands produce less perspiration. Skin perspires, what some people mistakenly call breathing. It takes in about 2. 5% of the body’s oxygen and releases about 3% carbon dioxide. In general, the skin does not breathe from outside oxygen. It works on anaerobic metabolism through our lungs. The skin is a bio-conversion factory. It is the largest hormone and enzyme producing organ of the body. Two distinct layers make up the skin. The epidermis, which covers and protects and the dermis, supports the epidermis and connects it to the underlying muscles. It acts as a heat regular in conjunction with the blood stream and perspiration glands. When the body is exposed to too much heat, there is a rush of blood to the surface of the skin, permitting it to cool. At the same time, the perspiration glands secrete liquid to aid in the process. Sensory erception occurs in the skin, preventing damage to its ability to feel heat and/or cold, giving pleasure by the same ability to feel such things as the smoothness of satin of the softness of down. There is delayed light screening by means of melanin’s reaction to light. Melanin is a dark pigment found in the skin. It is the area where both sebum and perspiration production take place and where these two combine on the surface to form a protective film (acid mantle) which renders the skin less vulnerable to damage and attack by environmental factors (e. . sun, wind, bacteria) and less prone to dehydration. â€Å"pH† is a chemist’s term standing for â€Å"potential of hydrogen† and is used to describe the degree of acidity or alkalinity in the acid mantle of the skin or in a product. It is measured on a scale ranging from 0-14. The centre of the scale, 7, is neutrality (neither acid nor alkaline). A reading above 7 indicates that the substance being measured is alkaline; below 7, acid. As far as the skin is concerned, a normal pH (or normal Acid Mantle) is in the range of 4. 2 to 5. 6. It will vary from one part of the body to another and generally speaking, the pH of a man’s skin is lower (more acid) than of a woman’s. The Chemical Composition of the Skin: Water70. 0% All percentages are approximate, Protein25. 5%as water may range from 60% to 70%. Lipids2. 0% Trace Minerals0. 5% All Other2. 0% There are three main skin layers: †¢The Subcutis contains fat cells and Lipocytes which make lipids. †¢The Dermis contains nerves, blood vessels, sebaceous glands and sweat glands and consists mainly of collagen & elastin. †¢The Epidermis contains keratinocytes, melanocytes and Langerhans cells. The skin, and in fact our whole body, is composed of many different types of cells. These cells have the same fundamental chemical composition but they vary in size, shape and function. The cells that comprise the outer layer of the skin are themselves a series of many layers that overlap each other, thus ensuring that cellular or other fluids cannot escape from the body via the skin except through a cut or break, or by means of special escape routes: the pore of follicles. The outer surface of the skin is comprised of flattened dead cells. Underneath however, there are living cells, which are somewhat fuller, and the deeper one goes into the skin, the fuller and rounder the cells become. At the bottom of all the layers, there is a row of cells, which are the ones that are always growing and in the process, pushing other cells upward, the cells become flattened as they are emptied of their natural fluid through pressure and dehydration. This normal process of shedding and renewal takes about 30 days (which means that after a cell is born in the bottom layer, it ends up on the surface of the skin, dead and ready to shed). The number of things the skin does for us is incredible. It covers us (epidermis and dermis), helps us keep warm (fatty layer), cools us off (sweat glands), keeps itself supple (oil glands) provides ultraviolet ray protection (melanin cells, registers our sense of touch (nerves), and is ornamental (hair, eyelashes, nails). Over time, dead protein cells can build up and block sebaceous and sudoriferous glands. This causes disturbances in the skins pH levels, normal rhythm and proliferation.