subject: The nature of the human skin [print this page] Author: omokaro morrison Author: omokaro morrison
The skin is the outer covering of the body. In humans, it is the largest organ of the integumentary system made up of multiple layers of ectodermal tissue, and guards the underlying muscles, bones, ligaments and internal organs.The Human skin is not unlike that of most other mammals except that it is not protected by a pelt and appears hairless though in fact nearly all human skin is covered with hair follicles. There are two general types of skin, hairy and glabrous skin. Because it interfaces with the environment, skin plays a key role in protecting (the body) against pathogens and excessive water loss. Its other functions are insulation, temperature regulation, sensation, synthesis of vitamin D, and the protection of vitamin B folates. Severely damaged skin will try to heal by forming scar tissue. This is often discolored and depigmented. In humans, skin pigmentation varies among populations, and skin type can range from dry to oily. Such skin variety provides a rich and diverse habit for bacteria which number roughly a 1000 species from 19 phyla.[5][6] Skin 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, malignat 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 skincolor.[7] 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 meters (16.1-21.5 sq ft.), most of it is between 23mm (0.10inch) thick. The average square inch (6.5cm) of skin holds 650 sweat glands, 20 blood vessels, 60,000 melanocytes, and more than a thousand nerve endings. Skin performs the following functions: Protection: an anatomical barrier from pathogens and damage between the internal and external environment in bodily defense; Langerhans cells in the skin are part of the adaptive immune system.[3][4] Sensation: contains a variety of nerve endings that react to heat and cold, touch, pressure, vibration, and tissue injury; see somatosensory system and haptics. Heat regulation: the skin contains a blood supply far greater than its requirements which allows precise control of energy loss by radiation, convection and conduction. Dilated blood vessels increase perfusion and heatloss, while constricted vessels greatly reduce cutaneous blood flow and conserve heat. Control of evaporation: the skin provides a relatively dry and semi-impermeable barrier to fluid loss. Loss of this function contributes to the massive fluid loss in burns. Aesthetics and communication: others see our skin and can assess our mood, physical state and attractiveness. Storage and synthesis: acts as a storage center for lipids and water, as well as a means of synthesis of vitamin D by action of UV on certain parts of the skin. Excretion: sweat contains urea, however its concentration is 1/130th that of urine, hence excretion by sweating is at most a secondary function to temperature regulation. Absorption: In addition, medicine can be administered through the skin, by ointments or by means of adhesive patch, such as the nicotine patch or iontophoresis. The skin is an important site of transport in many other organisms. Water resistance: The skin acts as a water resistant Know your skin type. Generally there are four skin types: oily, dry, sensitive and combination. Dry Skin: If your skin has a strong tendency toward dehydration, lacks oil, and has few breakouts if any at all, it is considered dry. In more extreme cases, dry skin lacks elasticity and can be extremely sensitive to the sun, wind, and cold temperatures. Wash your face once a day with a rich, creamy cleanser and warm water. Rinse with warm water and pat your skin dry. Use toner to help with that tight and flaky feeling of dehydration. Avoid toners and makeup that contain alcohol as alcohol-based products have a drying effect on skin. Oily Skin:If your skin is oily, it usually has a lot of shine to it very soon after cleansing and the pores are generally slightly enlarged. It is more prone to pimples, blackheads, and whiteheads than other skin types and is coarser in texture. Your skin tends to attract more dirt than dry skin, so wash your face twice a day with a gentle non-foaming cleanser and warm water. Rinse with warm water. Use an alcohol-free, hydrating toner to help remove additional residue. Oil blotting sheets through out the day can help control shine, and it takes as little as 3 minutes after lunch. Normal Skin: Some consider normal skin to be Combination skin, but it is not. If your skin is marked by oily skin in the T zone and dry, taut skin on the cheeks, and changes with seasons (dryer in winter, oilier in summer) it is considered normal. Normal skins can also be 'Normal-To's' as in normal to oily or normal to dry. Wash your face with cleansers that are designed for your normal/normal-to skin type. Wipe an alcohol free, hydrating toner all over the face. Apply moisturizer more frequently to dry skin. Sensitive Skin: Please note that may have sensitive skin AND normal, oily, or dry. If your skin has allergic reactions to beauty products and is usually sensitive to the sun, wind, and cold weather, it is sensitive. Sensitivity can show up in rashiness, redness, inflammation, acne, and dilated capillaries. Look for cleansers, toners, makeup, and moisturizers that are fragrance-free and hypoallergenic. Cleanse, tone and moisturize with gentle products everyday. The idea for your skin is to always choose products with a soothing benefit. Some common ingredients to look for are: chamomile, azulene, bisabolol, allantoin, lavender, camphor, calamine, rosemary, thyme, aloe vera etc. Combination Skin: Combination skin is truly two extreme skin types on one face. These situations occur when there is acne and a lot of oil in one area when the rest of the skin is generally not producing oil and dry. Two common examples are a dry skin with papular and pustular acne on the cheeks or a normal skin with inflamed papular and pustular acne in the chin and mouth area. For Combination skins, treat each area appropriatly as described above. If the acne is severe, consult a dermatologist or esthetician.You need to watch out for your skin. Learn more general tips on how to care for your skin at www.extraskincare.blogspot.comAbout the Author:
My name is omokaro morrison .I was born april 9th 1984, i am a student of university of benin,Nigeria.The skin and is functions was a topic i enjoyed in biology classes in my secondary school days ,although i am now studying mechanical Engineering i just want to help in spreading the knowledge of the skin and its properties so that a lot of persons can easily learn how to develop an healthy skin
