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Encyclopedia > Skin

In zootomy and dermatology, skin is the largest organ of the integumentary system made up of multiple layers of epithelial tissues that guard underlying muscles and organs.[1] Skin pigmentation (see: human skin color or coloring) varies among populations, and skin type can range from dry skin to oily skin. Skins redirects here. ... Skin or Skins can refer to: Skin, an organ of the integumentary system (also see nudity) Skin (singer), lead singer of the band Skunk Anansie Skin (television), a 2003 Fox television show Skins (TV series), a 2007 British television series Skin (short story), a story written by Roald Dahl Skin... Image File history File linksMetadata Skin. ... Image File history File linksMetadata Skin. ... Cross-section of all skin layers Optical coherence tomography tomogram of fingertip, depicting stratum corneum (~500µm thick) with stratum disjunctum on top and stratum lucidum (connection to stratum spinosum) in the middle. ... The dermis is a layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. ... The distribution of the bloodvessels in the skin of the sole of the foot. ... A hair follicle is part of the skin that grows hair by packing old cells together. ... In humans, there are four kinds of sudoriferous or sweat glands which differ greatly in both the composition of the sweat and its purpose. ... Schematic view of a hair follicle with sebaceous gland. ... Zootomy is a contraction of zoological and anatomy and refers to the dissection of animals as opposed to that of plants (phytotomy) See also: Androtomy, zootomical terms for location, Cat anatomy La Anatomía comparada estudia diversas especies. ... Dermatology (from Greek δερμα, skin) is a branch of medicine dealing with the skin and its appendages (hair, sweat glands, etc). ... This article is about the biological unit. ... In zootomy, the integumentary system is the external covering of the body, comprising the skin, hair, scales, nails, sweat glands and their products (sweat and mucus). ... In zootomy, epithelium is a tissue composed of a layer of cells. ... Biological tissue is a collection of interconnected cells that perform a similar function within an organism. ... For other uses of Muscles, see Muscles (disambiguation). ... This article is about the biological unit. ... Human skin color can range from very dark brown to nearly colorless (appearing pinkish white due to the blood in the skin) in different people. ... Xeroderma literally means dry skin. It is a condition involving the integumentary system, which in most cases can safely be treated with emollients and/or moisturizers. ...


The adjective cutaneous literally means "of the skin" (from Latin cutis, skin).


Because it interfaces with the surroundings skin plays a very important role in protecting (the body) against pathogens. Its other functions are insulation, temperature regulation, sensation, synthesis of vitamin D, and the protection of vitamin B folates. A pathogen (from Greek pathos, suffering/emotion, and gene, to give birth to), infectious agent, or more commonly germ, is a biological agent that causes disease or illness to its host. ... Thermal insulation on the Huygens probe The term thermal insulation can refer to materials used to reduce the rate of heat transfer, or the methods and processes used to reduce heat transfer. ... For other uses, see Temperature (disambiguation). ... Vitamin D is a fat soluble vitamin that contributes to the maintenance of normal levels of calcium and phosphorus in the bloodstream. ... Vitamin B is a complex of several vitamins. ...


Severely damaged skin will try to heal by forming scar tissue. This is often discolored and depigmented. This article does not cite any references or sources. ...


The use of natural or synthetic cosmetics to treat the appearance of the face and condition of the skin (such as pore control and black head cleansing) is common among many cultures. Oily skin is caused by hormonal fluctuations. This leads to a DHT sensitivity. This abnormal sensitivity causes the skin to lose moisture and essential fatty acids (linoleic acid in particular). When thousands of skin cells die the skin compensates for this loss of moisture by producing higher levels of oil.[2] Oily skin can be cleaned quickly with a mild solution of detergent,[1] when pure bath soaps fail (see below: Hygiene). Afterward, body lotions could be used to recondition cleansed skin,[1] as would be used to treat dry skin. Make-up redirects here. ... A pore, in general, is some form of opening, usually very small. ... A black head (technically known as a comedo) is a yellowish, reddish (with white cap) or blackish bump or plug on a skin. ... For other uses, see DHT (disambiguation). ...

Contents

Skin components

Also see below: Skin layers, at bottom.

Skin has pigmentation, or melanin, provided by melanocytes, which absorb some of the potentially dangerous ultraviolet radiation (UV) in sunlight. It also contains DNA repair enzymes which help to 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.[3] Natural Ultramarine pigment in powdered form. ... Broadly, melanin is any of the polyacetylene, polyaniline, and polypyrrole blacks and browns or their mixed copolymers. ... This article or section does not cite its references or sources. ... Note: Ultraviolet is also the name of a 1998 UK television miniseries about vampires. ... Prism splitting light High Resolution Solar Spectrum Sunlight in the broad sense is the total spectrum of the electromagnetic radiation given off by the Sun. ... The structure of part of a DNA double helix Deoxyribonucleic acid, or DNA, is a nucleic acid molecule that contains the genetic instructions used in the development and functioning of all known living organisms. ... Ribbon diagram of the enzyme TIM, surrounded by the space-filling model of the protein. ... For other uses, see Gene (disambiguation). ... Skin cancer is a malignant growth on the skin which can have many causes. ... In medicine, malignant is a clinical term that means to be severe and become progressively worse, as in malignant hypertension. ... Melanoma is a malignant tumor of melanocytes which are found predominantly in skin but also in the bowel and the eye (see uveal melanoma). ... Metastasis (Greek: change of the state) is the spread of cancer from its primary site to other places in the body. ... Human skin color can range from very dark brown to nearly colorless (appearing pinkish white due to the blood in the skin) in different people. ...


Mammalian skin often contains hairs, which in sufficient density is called fur. The hair mainly serves to augment the insulation the skin provides, but can also serve as a secondary sexual characteristic or as camouflage. On some animals, the skin is very hard and thick, and can be processed to create leather. Reptiles and fish have hard protective scales on their skin for protection, and birds have hard feathers, all made of tough β-keratins. Amphibian skin is not a strong barrier to passage of chemicals and is often subject to osmosis. A frog sitting in an anesthetic solution could quickly go to sleep. Subclasses & Infraclasses Subclass †Allotheria* Subclass Prototheria Subclass Theria Infraclass †Trituberculata Infraclass Metatheria Infraclass Eutheria For the folk-rock band see The Mammals. ... For other uses, see Fur (disambiguation). ... For the 1968 stage production, see Hair (musical), for the 1979 film, see Hair (film). ... A peacock displays his long, colored feathers, an example of his secondary sexual characteristics. ... This article is about protective camouflage used to disguise people, animals, or military targets. ... For other uses, see Leather (disambiguation). ... Reptilia redirects here. ... For other uses, see Fish (disambiguation). ... For other uses, see Bird (disambiguation). ... Not to be confused with kerogen or carotene. ... ‹ The template below (Citations missing) is being considered for deletion. ... Osmosis is the spontaneous net movement of water across a semipermeable membrane from a region of low solute concentration to a solution with a high solute concentration, down a solute concentration gradient. ... Distribution of frogs (in black) Suborders Archaeobatrachia Mesobatrachia Neobatrachia - List of Anuran families The frogness babe is an amphibian in the order Anura (meaning tail-less from Greek an-, without + oura, tail), formerly referred to as Salientia (Latin saltare, to jump). ... Anesthesia (AE), also anaesthesia (BE), is the process of blocking the perception of pain and other sensations. ...


The skin is often known as the largest organ of the human body. This applies to exterior surface, as it covers the body, appearing to have the largest surface area of all the organs. Moreover, it applies to weight, as it weighs more than any single internal organ, accounting for about 15 percent of body weight on average, or roughly 6 pounds (2.7 kilograms). 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.


Functions

Skin performs the following functions:

  1. 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
  2. Sensation: contains a variety of nerve endings that react to heat and cold, touch, pressure, vibration, and tissue injury; see somatosensory system and haptics.
  3. 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 heat loss while constricted vessels greatly reduce cutaneous blood flow and conserve heat. Erector pili muscles are significant in animals.
  4. Control of evaporation: the skin provides a relatively dry and impermeable barrier to fluid loss. Loss of this function contributes to the massive fluid loss in burns.
  5. Aesthetics and communication: others see our skin and can assess our mood, physical state and attractiveness.
  6. 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.
  7. 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.
  8. Absorption: Oxygen, nitrogen and carbon dioxide can diffuse into the epidermis in small amounts, some animals using their skin for their sole respiration organ. 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.
  9. Water resistance: The skin acts as a water resistant barrier so essential nutrients aren't washed out of the body

Langerhans cells are immature dendritic cells containing large granules called Birbeck granules. ... The immune system is the collection of organs and tissues involved in the adaptive defense of a body against foreign biological material. ... It has been suggested that this article or section be merged with Sensation and perception psychology. ... A thermoreceptor is a sensory receptor that responds to temperature, primarily within the innocuous range. ... Somatic sensation consists of the various sensory receptors that trigger the experiences labelled as touch or pressure, temperature (warm or cold), pain (including itch and tickle), and the sensations of muscle movement and joint position including posture, movement, and facial expression (collectively also called proprioception). ... This article is about the study of touching behaviour in humans. ... The arrector pili muscle is a minute muscle found in the epidermal layer of the skin. ... For other uses, see Burn. ... Vitamin D is a fat soluble vitamin that contributes to the maintenance of normal levels of calcium and phosphorus in the bloodstream. ... Note: Ultraviolet is also the name of a 1998 UK television miniseries about vampires. ... SWEAT is an OLN/TSN show hosted by Julie Zwillich that aired in 2003-2004. ... Urea is an organic compound with the chemical formula (NH2)2CO. Urea is also known as carbamide, especially in the recommended International Nonproprietary Names (rINN) in use in Europe. ... This article is about the urine of animals generally. ... The kidneys are important excretory organs in vertebrates. ... Breathing / Respiration organs are used by most, or all, animals to exchange the gasses necessary for their life functions, known as respiration. ... A 21mg dose Nicoderm CQ patch applied to the right arm A transdermal patch or skin patch is a medicated adhesive patch that is placed on the skin to deliver a time released dose of medication through the skin and into the bloodstream. ... A nicotine patch is a transdermal patch that releases nicotine into the body through the skin. ... Iontophoresis is a non-invasive method of propelling high concentrations of a charged substance, normally medication or bioactive-agents, transdermally by repulsive electromotive force using a small electrical charge applied to an iontophoretic chamber containing a similarly charged active agent and its vehicle. ...

Hygiene

See also: Exfoliation (cosmetology)

Unclean skin favors the development of pathogenic organisms – the dead cells that continually slough off of the epidermis mix with the secretions of the sweat and sebaceous glands and the dust found on the skin to form a filthy layer on its surface. If not washed away, the slurry of sweat and sebaceous secretions mixed with dirt and dead skin is decomposed by bacterial flora, producing a foul smell. Functions of the skin are disturbed when it is excessively dirty; it becomes more easily damaged, the release of antibacterial compounds decreases, and dirty skin is more prone to develop infections. Cosmetics should be used carefully because these may cause allergic reactions. Each season requires suitable clothing in order to facilitate the evaporation of the sweat. Sunlight, water and air play an important role in keeping the skin healthy. This article or section does not cite its references or sources. ...


The skin supports its own ecosystems of microorganisms, including yeasts and bacteria, which cannot be removed by any amount of cleaning. Estimates place the number of individual bacteria on the surface of one square inch (6.5 square cm) of human skin at 50 million though this figure varies greatly over the average 20 feet2 (1.9 m²) of human skin. Oily surfaces, such as the face, may contain over 500 million bacteria per square inch (6.5 cm²). Despite these vast quantities, all of the bacteria found on the skin's surface would fit into a volume the size of a pea.[4] In general, the microorganisms keep one another in check and are part of a healthy skin. When the balance is disturbed, there may be an overgrowth and infection, such as when antibiotics kill microbes, resulting in an overgrowth of yeast. The skin is continuous with the inner epithelial lining of the body at the orifices, each of which supports its own complement of microbes. For other uses, see Ecological Systems Theory. ... A cluster of Escherichia coli bacteria magnified 10,000 times. ... Typical divisions Ascomycota (sac fungi) Saccharomycotina (true yeasts) Taphrinomycotina Schizosaccharomycetes (fission yeasts) Basidiomycota (club fungi) Urediniomycetes Sporidiales Yeasts are a growth form of eukaryotic micro organisms classified in the kingdom Fungi, with about 1,500 species described;[1] they dominate fungal diversity in the oceans. ... Phyla Actinobacteria Aquificae Chlamydiae Bacteroidetes/Chlorobi Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Lentisphaerae Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Verrucomicrobia Bacteria (singular: bacterium) are unicellular microorganisms. ... Staphylococcus aureus - Antibiotics test plate. ... A microorganism or microbe is an organism that is so small that it is microscopic (invisible to the naked eye). ... In zootomy, epithelium is a tissue composed of a layer of cells. ...


Oily skin is caused by over-active glands, that produce a substance called sebum, a naturally healthy skin lubricant.[1] When the skin produces excessive sebum, it becomes heavy and thick in texture. Oily skin is typified by shininess, blemishes and pimples.[1] The oily-skin type is not necessarily bad, since such skin is less prone to wrinkling, or other signs of aging,[1] because the oil helps to keep needed moisture locked into the epidermis (outermost layer of skin). The sebaceous glands are glands found in the skin of mammals. ... The sebaceous glands are glands found in the skin of mammals. ... A pimple is a type of skin lesion caused by inflamed and/or obstructed pores. ... Cross-section of all skin layers Optical coherence tomography tomogram of fingertip, depicting stratum corneum (~500µm thick) with stratum disjunctum on top and stratum lucidum (connection to stratum spinosum) in the middle. ...


The negative aspect of the oily-skin type is that oily complexions are especially susceptible to clogged pores, blackheads, and buildup of dead skin cells on the surface of the skin.[1] Oily skin can be sallow and rough in texture and tends to have large, clearly visible pores everywhere, except around the eyes and neck.[1] This article is about the skin condition. ...


The goal of treating oily skin is to remove excess surface sebum without complete removal of skin lipids.[1] Severe degreasing treatment can foster an actual worsening of sebum secretion, which defeats the aim of the cleansing.[1] A method of cleansing oily skin is to wash with a solution of a mild synthetic detergent[1] (see: surfactant) containing no oils, waxes or other lipid agents that could aggravate the oily condition of the skin, sometimes combined with a toning lotion. Such a product removes the oily residue and debris from the skin surface. Some cleansing products have lower concentrations of hydroxy acids, which remove dead cells from the upper levels of the stratum corneum.[1] Those products should be used on a regular basis to work adequately.[1] A light moisturizer may be included in a product to counteract any drying effects of the cleanser.[1] Figure 1: Basic lipid structure. ... Laundry detergents are just one of many possible uses for detergents Detergent is a compound, or a mixture of compounds, intended to assist cleaning. ... Surfactants, also known as tensides, are wetting agents that lower the surface tension of a liquid, allowing easier spreading, and lower the interfacial tension between two liquids. ... candle wax This page is about the substance. ... α-Hydroxy Acids (AHAs) are naturally occurring carboxylic acids which are well-known for their use in the cosmetics industry. ... The stratum corneum (the horny layer) is the outermost layer of the epidermis (the outermost layer of the skin). ...


Aging

For more details on this topic, see senescence.
A typical rash
A typical rash
Skin infected with Scabies
Skin infected with Scabies

As skin ages, it becomes thinner and more easily damaged. Intensifying this effect is the decreasing ability of skin to heal itself as a person ages. In biology, senescence is the combination of processes of deterioration which follow the period of development of an organism. ... Image File history File links Download high resolution version (800x633, 60 KB)Rash caused by an unusual reaction File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Image File history File links Download high resolution version (800x633, 60 KB)Rash caused by an unusual reaction File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Image File history File linksMetadata Scabies-burrow. ... Image File history File linksMetadata Scabies-burrow. ...


Skin aging is caused by the fall in elasticity. Aging skin also receives less blood flow and lower gland activity.


Disease

For more details on this topic, see list of skin diseases.

In medicine, the branch concerned with the skin is called dermatology. The skin is subject to constant attack and, so, can be afflicted by numerous ailments such as these: This is a list of diseases of the skin. ... For the chemical substances known as medicines, see medication. ... Dermatology (from Greek δερμα, skin) is a branch of medicine dealing with the skin and its appendages (hair, sweat glands, etc). ...


Tumors:

Others: [[sites:]] arises from the stratified squamous epithelium of the skin , lip , oral cavity, tongue, pharynx , larynx, oesophagus, cervix, vagina and anal canal. ... Skin cancer is a malignant growth on the skin which can have many causes. ...

There are several other skin diseases as well. A rash is a change in skin which affects its color, appearance, or texture. ... For the packaging type, see Blister pack. ... Keratosis pilaris (KP) is a very common genetic follicular condition that is manifested by the appearance of rough bumps on the skin and hence colloquially referred to as chicken skin. It most often appears on the back and outer sides of the upper arms (though the lower arms can also... For the fictional character, see Fungus the Bogeyman. ... Athletes foot or Tinea pedis[1] is a parasitic fungal infection of the epidermis of the foot. ... This article is about the fungal infection. ... A microorganism or microbe is an organism that is so small that it is microscopic (invisible to the naked eye). ... Calcinosis cutis (or cutaneous calcification) is a type of calcinosis wherein calcium deposits form in the skin. ... A keloid is a special type of scar which results in an overgrowth of tissue at the site of a healed skin injury. ... Not to be confused with alphos, a form of leprosy once called vitiligo. ... Albino redirects here. ... For the beetle, see Exema. ...


Variability in skin tone

Individuals with ancestors from different parts of the world can have highly visible differences in skin pigmentation. Individuals with Sub-Saharan African ancestry (black people) tend towards darker skin, while those of Northern European descent (white people) have paler skin. Between these extremes are individuals of Asian, South-East Asian, Native American, Middle Eastern, Polynesian and Melanesian descent. Satellite image of Africa, showing the ecological break that defines the sub-Saharan area African countries considered sub-Saharan Sub-Saharan Africa is a geographical term used to describe the area of the African continent which lies south of the Sahara, or those African countries which are fully or partially... Though most indigenous Africans possess relatively dark skin, they exhibit much variation in physical appearance. ... Northern Europe Northern Europe is the northern part of the European continent. ... Whites redirects here. ... For other uses, see Asia (disambiguation). ... Location of Southeast Asia Southeast Asia is a subregion of Asia. ... This article is about the people indigenous to the United States. ... A map showing countries commonly considered to be part of the Middle East The Middle East is a region comprising the lands around the southern and eastern parts of the Mediterranean Sea, a territory that extends from the eastern Mediterranean Sea to the Persian Gulf. ... Carving from the ridgepole of a Māori house, ca 1840 Polynesia (from Greek: πολύς many, νῆσος island) is a large grouping of over 1,000 islands scattered over the central and southern Pacific Ocean. ... map of Melanesia Melanesia (from Greek: μέλας black, νῆσος island) is a subregion of Oceania extending from the western side of the West Pacific to the Arafura Sea, north and northeast of Australia. ...


The skin of black people has more variation in color from one part of the body to another than does the skin of other racial groups, particularly the palms of the hands and soles of the feet. Part of this is the result of the variations in the thickness of the skin or different parts of the body. The thicker the skin, the more layers of cell with melanin in them, and the darker the color.[5] In addition, these parts of the body do not have melanin-producing cells. Though most indigenous Africans possess relatively dark skin, they exhibit much variation in physical appearance. ...


Darker skin hinders UV A rays from penetrating. Since vitamin B folats are degraded by UV A and vitamin D is synthesized different skin tones are more likely to produce different vitamin deficiencies.


Animal skin products

The term skin refers to the covering of a small animal, such as a sheep, goat (goatskin), pig, snake (snakeskin) etc or the young of a large animal. Goatskin is the skin of a goat, or the leather made from it. ... Snakeskin is a material that is produced from the hide of a snake. ...


The term hides or rawhide refers to the covering of a large adult animal such as a cow, buffalo, horse etc. Hides are skins obtained from animals that are used for human use. ... Rawhide is a hide or animal skin that has not been exposed to tanning and thus is much lighter in color than treated animal hides. ...


Skins and hides from different animals are used for clothing, bags and other consumer products, usually in the form of leather, but also furs. For other uses, see Leather (disambiguation). ... For other uses, see Fur (disambiguation). ...


Skin can also be used to make products such as gelatin, glue and wool. Mucus of skin from hagfish is still under research. For the art collective, see Gelitin. ... An animal glue is an adhesive that is created by prolonged boiling of animal connective tissue. ... For other uses, see Wool (disambiguation). ... Genera Eptatretus Myxine Nemamyxine Neomyxine Notomyxine Paramyxine Quadratus This article is about the Hagfish. ...


Skin layers

Skin is composed of three primary layers: the epidermis, which provides waterproofing and serves as a barrier to infection; the dermis, which serves as a location for the appendages of skin; and the hypodermis (subcutaneous adipose layer). Cross-section of all skin layers Optical coherence tomography tomogram of fingertip, depicting stratum corneum (~500µm thick) with stratum disjunctum on top and stratum lucidum (connection to stratum spinosum) in the middle. ... The dermis is a layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. ... A limb (from the Old English lim) is a jointed appendage of the human or animal branch of a tree; a representative, branch or member of a group or organization. ... The hypodermis is the lowermost layer of the integumentary system, which is present only in more recently-evolved vertebrates. ...


Epidermis

Epidermis, "epi" coming from the Greek meaning "over" or "upon", is the outermost layer of the skin. It forms the waterproof, protective wrap over the body's surface and is made up of stratified squamous epithelium with an underlying basal lamina. This article is about the epithelium as it relates to animal anatomy. ... The basal lamina (often erroneously called basement membrane) is a layer on which epithelium sits. ...


The outermost epidermis consists of stratified squamous epithelium with an underlying connective tissue section, or dermis, and a hypodermis, or basement membrane. The epidermis contains no blood vessels, and cells in the deepest layers are nourished by diffusion from blood capillaries extending to the upper layers of the dermis. The main type of cells which make up the epidermis are keratinocytes, with melanocytes and Langerhans cells also present. The epidermis can be further subdivided into the following strata (beginning with the outermost layer): corneum, lucidum (only in palms of hands and bottoms of feet), granulosum, spinosum, basale. Cells are formed through mitosis at the basale layer. The daughter cells, (see cell division) move up the strata changing shape and composition as they die due to isolation from their blood source. The cytoplasm is released and the protein keratin is inserted. They eventually reach the corneum and slough off (desquamation). This process is called keratinization and takes place within about 27 days. This keratinized layer of skin is responsible for keeping water in the body and keeping other harmful chemicals and pathogens out, making skin a natural barrier to infection. Stratification is the building up of layers of deposits, and can have several variations of meaning: Social stratification, is the dividing of a society into levels based on wealth or power. ... Squamous means covered with or formed of scales; scaly. ... This article is about the epithelium as it relates to animal anatomy. ... ... f you all The blood vessels are part of the circulatory system and function to transport blood throughout the body. ... The keratinocyte is the major cell type of the epidermis, making up about 90% of epidermal cells. ... This article or section does not cite its references or sources. ... Langerhans cells are immature dendritic cells containing large granules called Birbeck granules. ... Mitosis divides genetic information during cell division. ... This does not adequately cite its references or sources. ... Not to be confused with kerogen or carotene. ... Desquamation is the shedding of the outer layers of the skin. ... A pathogen (literally birth of pain from the Greek παθογένεια) is a biological agent that can cause disease to its host. ...

[also see:  image rotating (1.1 mb) ] Optical Coherence Tomography tomogram of fingertip, depicting stratum corneum (~500µm thick) with stratum disjunctum on top and stratum lucidum (connection to stratum spinosum) in the middle. At the bottom superficial parts of the dermis. Sweatducts are clearly visible.
[also see:   image rotating (1.1 mb) ]
Optical Coherence Tomography tomogram of fingertip, depicting stratum corneum (~500µm thick) with stratum disjunctum on top and stratum lucidum (connection to stratum spinosum) in the middle. At the bottom superficial parts of the dermis. Sweatducts are clearly visible.

Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... Image File history File links HautFingerspitzeOCT.gif‎ Optical Coherence Tomography tomogram of fingertip, depicting stratum corneum (~500µm thick) with stratum disjunctum on top and stratum lucidum (connection to stratum spinosum) in the middle. ... The stratum corneum (the horny layer) is the outermost layer of the epidermis (the outermost layer of the skin). ... The Stratum Lucidum is one of the layers of the Epidermis. ... The dermis is a layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. ...

Components

The epidermis contains no blood vessels, and is nourished by diffusion from the dermis. The main type of cells which make up the epidermis are keratinocytes, melanocytes, Langerhans cells and Merkels cells. f you all The blood vessels are part of the circulatory system and function to transport blood throughout the body. ... diffusion (disambiguation). ... The dermis is a layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. ... The keratinocyte is the major cell type of the epidermis, making up about 90% of epidermal cells. ... This article or section does not cite its references or sources. ... Langerhans cells are immature dendritic cells containing large granules called Birbeck granules. ... Merkel cells are large oval cells found in the skin of vertebrates. ...


Layers

Epidermis is divided into several layers where cells are formed through mitosis at the innermost layers. They move up the strata changing shape and composition as they differentiate and become filled with keratin. They eventually reach the top layer called stratum corneum and become sloughed off, or desquamated. This process is called keratinization and takes place within weeks. The outermost layer of Epidermis consists of 25 to 30 layers of dead cells. Mitosis divides genetic information during cell division. ... Not to be confused with kerogen or carotene. ... Epidermis is the outermost layer of the skin. ...


Sublayers

Epidermis is divided into the following 5 sublayers or strata:

Mnemonics that are good for remembering the layers of the skin (using "stratum basale" instead of "stratum germinativum"): The stratum corneum (the horny layer) is the outermost layer of the epidermis (the outermost layer of the skin). ... The Stratum Lucidum is one of the layers of the Epidermis. ... Stratum granulosum contains 3 to 5 rows of flattened cells whose cytoplasm contains small granules. ... It is a multiple-layered arrangement of cuboidal cells containing molecular bridges that conect them to adjacent cells. ... Stratum germinativum (also stratum basale or basal cell layer) is the layer of keratinocytes that lies at the base of the epidermis immediately above the dermis. ... For other uses, see Mnemonic (disambiguation). ...

  • "Cher Likes Getting Skin Botoxed" (from superficial to deep)
  • "Before Signing, Get Legal Counsel" (from deep to superficial)


Blood capillaries are found beneath the epidermis, and are linked to an arteriole and a venule. Arterial shunt vessels may bypass the network in ears, the nose and fingertips.

Dermis
The distribution of the bloodvessels in the skin of the sole of the foot. (Corium - TA alternate term for dermis - is labeled at upper right.)
A diagrammatic sectional view of the skin (click on image to magnify). (Dermis labeled at center right.)
Gray's subject #234 1065
MeSH Dermis
Dorlands/Elsevier d_11/12289496

Image File history File links Gray942. ... Image File history File links Gray940. ... Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. ... Elseviers logo. ...

Dermis

The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many Mechanoreceptor/nerve endings that provide the sense of touch and heat. It contains the hair follicles, sweat glands, sebaceous glands, apocrine glands, lymphatic vessels and blood vessels. The blood vessels in the dermis provide nourishment and waste removal to its own cells as well as the Stratum basale of the epidermis. Cross-section of all skin layers Optical coherence tomography tomogram of fingertip, depicting stratum corneum (~500µm thick) with stratum disjunctum on top and stratum lucidum (connection to stratum spinosum) in the middle. ... Connective tissue is one of the four types of tissue in traditional classifications (the others being epithelial, muscle, and nervous tissue. ... ... A hair follicle is part of the skin that grows hair by packing old cells together. ... Sweating (also called perspiration or sometimes transpiration) is the loss of a watery fluid, consisting mainly of sodium chloride and urea in solution, that is secreted by the sweat glands in the skin of mammals. ... The sebaceous glands are glands found in the skin of mammals. ... ... In mammals including humans, the lymphatic vessels (or lymphatics) are a network of thin tubes that branch, like blood vessels, into tissues throughout the body. ... The blood vessels are part of the circulatory system and function to transport blood throughout the body. ...


Structure


The dermis is structurally divided into two areas: a superficial area adjacent to the epidermis, called the papillary region, and a deep thicker area known as the reticular region.


Papillary region

The papillary region is composed of loose areolar connective tissue. It is named for its fingerlike projections called papillae, that extend toward the epidermis. The papillae provide the dermis with a "bumpy" surface that interdigitates with the epidermis, strengthening the connection between the two layers of skin. Gel-like matrix with all three fiber types Areoloar tissue is the most common connnective tissue type and can be found in the skin as well as in places that connect epithelium to other tissues. ...


In the palms, fingers, soles, and toes, the influence of the papillae projecting into the epidermis forms contours in the skin's surface. These are called friction ridges, because they help the hand or foot to grasp by increasing friction. Friction ridges occur in patterns (see: fingerprint) that are genetically and epigenetically determined and are therefore unique to the individual, making it possible to use fingerprints or footprints as a means of identification. For other uses, see Friction (disambiguation). ... This article is about human fingerprints. ... Epigenetic inheritance is the transmission of information from a cell or multicellular organism to its descendants without that information being encoded in the nucleotide sequence of the gene. ...


Reticular region

The reticular region lies deep in the papillary region and is usually much thicker. It is composed of dense irregular connective tissue, and receives its name from the dense concentration of collagenous, elastic, and reticular fibers that weave throughout it. These protein fibers give the dermis its properties of strength, extensibility, and elasticity. Tropocollagen triple helix. ... Elasticity is a branch of physics which studies the properties of elastic materials. ... A representation of the 3D structure of myoglobin showing coloured alpha helices. ...


Also located within the reticular region are the roots of the hair, sebaceous glands, sweat glands, receptors, nails, and blood vessels. The root of the hair ends in an enlargement, the hair bulb, which is whiter in color and softer in texture than the shaft, and is lodged in a follicular involution of the epidermis called the hair follicle. ... The sebaceous glands are glands found in the skin of mammals. ... Sweating (also called perspiration or sometimes transpiration) is the loss of a watery fluid, consisting mainly of sodium chloride and urea in solution, that is secreted by the sweat glands in the skin of mammals. ... A cutaneous receptor is a types of sensory receptor found in the dermis or epidermis. ... For other uses, see Nail. ... The blood vessels are part of the circulatory system and function to transport blood throughout the body. ...


Tattoo ink is held in the dermis. Stretch marks from pregnancy are also located in the dermis.


The hypodermis is not part of the skin, and lies below the dermis. Its purpose is to attach the skin to underlying bone and muscle as well as supplying it with blood vessels and nerves. It consists of loose connective tissue and elastin. The main cell types are fibroblasts, macrophages and adipocytes (the hypodermis contains 50% of body fat). Fat serves as padding and insulation for the body. This article is about the skeletal organs. ... For other uses of Muscles, see Muscles (disambiguation). ... NIH/3T3 Fibroblasts A fibroblast is a type of cell that synthesizes and maintains the extracellular matrix of many animal tissues. ... A macrophage of a mouse stretching its arms to engulf two particles, possibly pathogens Macrophages (Greek: big eaters, from makros large + phagein eat) are cells within the tissues that originate from specific white blood cells called monocytes. ... Adipocytes are the cells that primarily compose adipose tissue, specialized in storing energy as fat. ...


Microorganisms like Staphylococcus epidermidis colonize the skin surface. The density of skin flora depends on region of the skin. The disinfected skin surface gets recolonized from bacteria residing in the deeper areas of the hair follicle, gut and urogenital openings. Species S. aureus S. caprae S. epidermidis S. haemolyticus S. hominis S. lugdunensis S. pettenkoferi S. saprophyticus S. warneri S. xylosus Staphylococcus (in Greek staphyle means bunch of grapes and coccos means granule) is a genus of Gram-positive bacteria. ...


See also

Look up Skin in
Wiktionary, the free dictionary.

Wiktionary (a portmanteau of wiki and dictionary) is a multilingual, Web-based project to create a free content dictionary, available in over 151 languages. ... There are very few or no other articles that link to this one. ... Anthropodermic bibliopegy is the practice of binding books in human skin. ... This article is about calluses and corns of human skin. ... Make-up redirects here. ... Plastic surgery is a general term for operative manual and instrumental treatment which is performed for functional or aesthetic reasons. ... Cutaneous structures arise from the epidermis and include a variety of features such as hair, feathers, claws and nails. ... This is a list of diseases of the skin. ... Dermatology (from Greek δερμα, skin) is a branch of medicine dealing with the skin and its appendages (hair, sweat glands, etc). ... This article is about human fingerprints. ... For the 1968 stage production, see Hair (musical), for the 1979 film, see Hair (film). ... A hair follicle is part of the skin that grows hair by packing old cells together. ... Human skin color can range from very dark brown to nearly colorless (appearing pinkish white due to the blood in the skin) in different people. ... In dermatology, hyperpigmentation is the darkening of an area of skin or nails caused by increased melanin. ... Meissners corpuscles (discovered by the anatomist Georg Meissner (1829-1903) are a type of mechanoreceptor and more specifically, a tactile corpuscle(corpusculum tactus). ... For other uses, see Nail. ... A Pacinian corpuscle is a structure that functions as a mechanoreceptor. ... Molecular structure of apigenin, a polyphenol antioxidant A polyphenol antioxidant is a type of antioxidant containing a polyphenolic substructure. ... SWEAT is an OLN/TSN show hosted by Julie Zwillich that aired in 2003-2004. ... Fascia, pronounced , is specialized connective tissue layer which surrounds muscles, bones, and joints, providing support, protection and giving structure to the body. ...

References

  1. ^ a b c d e f g h i j k l m n "Skin care" (analysis), Health-Cares.net, 2007, webpage: HCcare.
  2. ^ "Why Me, Why Now?" SkinMed.co.uk, 2007, webpage: [1].
  3. ^ Maton, Anthea; Jean Hopkins, Charles William McLaughlin, Susan Johnson, Maryanna Quon Warner, David LaHart, Jill D. Wright (1993). Human Biology and Health. Englewood Cliffs, New Jersey, USA: Prentice Hall. ISBN 0-13-981176-1. 
  4. ^ Theodor Rosebury. Life on Man: Secker & Warburg, 1969 ISBN 0-670-42793-4
  5. ^ Smith, Wilma and Burns, Catherine. (1999) "Managing the hair and skin of African American pediatric patients." Journal of Pediatric Health Care 13(2):72-8.

External links

  • Skin care - The British Association of Cosmetic Doctors
In zootomy, the integumentary system is the external covering of the body, comprising the skin, hair, scales, nails, sweat glands and their products (sweat and mucus). ... Cutis is the combined term for the epidermis and the dermis, the two outer layers of the skin. ... Cross-section of all skin layers Optical coherence tomography tomogram of fingertip, depicting stratum corneum (~500µm thick) with stratum disjunctum on top and stratum lucidum (connection to stratum spinosum) in the middle. ... The stratum corneum (the horny layer) is the outermost layer of the epidermis (the outermost layer of the skin). ... The Stratum Lucidum is one of the layers of the Epidermis. ... Stratum granulosum contains 3 to 5 rows of flattened cells whose cytoplasm contains small granules. ... It is a multiple-layered arrangement of cuboidal cells containing molecular bridges that conect them to adjacent cells. ... Stratum germinativum (also stratum basale or basal cell layer) is the layer of keratinocytes that lies at the base of the epidermis immediately above the dermis. ... The dermis is a layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. ... The subcutis is the layer of tissue directly underlying the cutis. ... Skin appendages are appendages that are associated with the skin and serve a particular function. ... Human submaxillary gland. ... In humans, there are four kinds of sudoriferous or sweat glands which differ greatly in both the composition of the sweat and its purpose. ... A diagrammatic sectional view of the skin (magnified). ... A diagrammatic sectional view of the skin (magnified). ... Schematic view of a hair follicle with sebaceous gland. ... For the 1968 stage production, see Hair (musical), for the 1979 film, see Hair (film). ... The root of the hair ends in an enlargement, the hair bulb, which is whiter in color and softer in texture than the shaft, and is lodged in a follicular involution of the epidermis called the hair follicle. ... A hair follicle is part of the skin that grows hair by packing old cells together. ... The inner or epidermic coat of the hair follicle is closely adherent to the root of the hair, and consists of two strata named respectively the outer and inner root sheaths; The outer root sheath corresponds with the stratum mucosum of the epidermis, and resembles it in the rounded form... The second layer of the inner root sheath of the hair consists of one or two layers of horny, flattened, nucleated cells, known as Huxleys layer. ... Henles layer is the third layer of the inner root sheath of the hair, consisting of a single layer of cubical cells with clear flattened nuclei. ... For other uses, see Nail. ... The eponychium of a pinky, or little finger. ... The lunula is the crescent shaped whitish area of the nail bed of a fingernail or toenail. ... In this SEM image of a butterfly wing the scales are clearly visible, and the tiny platelets on each individual scale are just barely visible in the striping. ... Two feathers Feathers are one of the epidermal growths that form the distinctive outer covering, or plumage, on birds. ... List of bones of the human skeleton Human anatomy is primarily the scientific study of the morphology of the adult human body. ... For other uses of the word head, see head (disambiguation). ... In humans, the adult skull is normally made up of 22 bones. ... In human anatomy, the forehead or brow is the bony part of the head above the eyes. ... For other uses, see Eye (disambiguation). ... For other uses, see Ear (disambiguation). ... The visible part of the human nose is the protruding part of the face that bears the nostrils. ... Sagittal section of nose mouth, pharynx, and larynx. ... For other uses, see Tongue (disambiguation). ... Teeth redirects here. ... The mandible (from Latin mandibÅ­la, jawbone) or inferior maxillary bone is, together with the maxilla, the largest and strongest bone of the face. ... For other uses, see Face (disambiguation). ... This article is about the anatomical feature. ... This article is about the part of the face. ... Image File history File links Human body features (external) Created by Vsion. ... For other uses, see Neck (disambiguation). ... For other uses, see Throat (disambiguation). ... For other uses, see Adams apple (disambiguation). ... The human torso Torso is an anatomical term for the greater part of the human body without the head and limbs. ... This article is about the body part. ... The vertebral column seen from the side Different regions (curvatures) of the vertebral column The vertebral column (backbone or spine) is a column of vertebrae situated in the dorsal aspect of the abdomen. ... For other uses, see Breast (disambiguation). ... The Tail of Spence (or Spences tail) is an extension of the tissue of the breast which extends into the axilla (armpit). ... Male Chest The chest is a part of the anatomy of humans and various other animals. ... The human rib cage is a part of the human skeleton within the thoracic area. ... The human abdomen (from the Latin word meaning belly) is the part of the body between the pelvis and the thorax. ... This article does not cite any references or sources. ... A sex organ, or primary sexual characteristic, as narrowly defined, is any of the anatomical parts of the body which are involved in sexual reproduction and constitute the reproductive system in a complex organism; in mammals, these are: Female: Bartholins glands, cervix, clitoris, Fallopian tubes, labia, ovaries, Skenes... The clitoris is a sexual organ that is present only in female mammals. ... The vagina, (from Latin, literally sheath or scabbard ) is the tubular tract leading from the uterus to the exterior of the body in female placental mammals and marsupials, or to the cloaca in female birds, monotremes, and some reptiles. ... The penis (plural penises, penes) is an external male sexual organ. ... In some male mammals the scrotum is a protuberance of skin and muscle containing the testicles. ... Look up testes in Wiktionary, the free dictionary. ... In anatomy, the hip is the bony projection of the femur which is known as the greater trochanter, and the overlying muscle and fat. ... This article is about the bodily orifice. ... Bottom commonly refers to the human buttocks but also has other uses. ... A limb (from the Old English lim) is a jointed, or prehensile (as octopus tentacles or new world monkey tails), appendage of the human or animal body; a large or main branch of a tree; a representative, branch or member of a group or organization. ... Look up ARM in Wiktionary, the free dictionary. ... For the band, see Elbow (band). ... // The Human Forearm The forearm is the structure on the upper limb, between the elbow and the wrist. ... For the municipality in Germany, see Wrist, Germany. ... For other uses, see Hand (disambiguation). ... This article does not cite any references or sources. ... For other uses, see Thumb (disambiguation). ... The second digit of a human hand is also referred to as the index finger, pointer finger, forefinger, trigger finger, digitus secundus, or digitus II. It is located between the first and third digits - that is, between the thumb and the middle finger. ... This article is about the vulgar gesture. ... The ring finger is the fourth digit of the human hand, and the second most ulnar finger, located between the middle finger and the little finger. ... The little finger, often called the pinky in American English and pinkie in Scottish English (from the Dutch word pink, meaning little finger), is the most ulnar and usually smallest finger of the human hand, opposite the thumb, next to the ring finger. ... In common usage, a human leg is the lower limb of the body, extending from the hip to the ankle, and including the thigh, the knee, and the cnemis. ... Manuel Márquez de León International Airport (IATA: LAP, ICAO: MMLP) is an international airport located at La Paz, Baja California Sur, Mexico. ... In humans the thigh is the area between the pelvis and buttocks and the knee. ... For other uses, see Knee (disambiguation). ... The calf or gastrosoleus is a pair of muscles—the gastrocnemius and soleus—at the back of the lower human leg. ... For other uses, see Heel (disambiguation). ... For a review of anatomical terms, see Anatomical position and Anatomical terms of location. ... For other uses, see Foot (disambiguation). ... This article is about the body part. ... Toes on foot. ... For the 1968 stage production, see Hair (musical), for the 1979 film, see Hair (film). ... Image File history File links Question_book-3. ...

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