Skin, Hair, and Nailsenparents skin protects the network of tissues, muscles, bones, nerves, blood vessels, and everything else inside our bodies. Hair and nails are actually modified types of, hair, nails, fingernails, toenails, hair loss, rash, rashes, body basics, perspiration, sweat, sun, fingers, toes, head, sweat glands, epidermis, subcutaneous tissue, melanin, melanocytes, keritinocytes, keratin, langerhans cells, infections, papillae, fingerprints, connective tissues, epidermal appendages, roots, follicles, papilla, medulla, cortex, cuticles, matrix, lunula, collagen, cuts, ecrine glands, apocrine glands, sebaceous glands, sebum, dryness, freckles, ringworm, tinea, dermatitis, eczema, impetigo, cellulitis, redness, streptococcal, staphylococcal, candida, athlete's foot, fungus, fungal infections itching, scalp, viruses, chicken pox, chickenpox, lice, scabies, acne, cancer, CD1Dermatology07/06/200012/20/201912/20/2019Larissa Hirsch, MD10/21/2019ff7f1929-9dfc-404b-91a9-b45e51633223<h3>What Does Skin Do?</h3> <p>Skin, our largest organ, has many jobs. It:</p> <ul> <li>protects the network of <a href="">muscles, bones</a>, nerves, blood vessels, and everything else inside our bodies</li> <li>forms a barrier that prevents harmful substances and <a href="">germs</a> from entering the body</li> <li>protects body tissues against injury</li> <li>helps control body temperature through sweating when we're hot and by helping keep heat in the body when we're cold</li> </ul> <p>Without the nerve cells in skin, people couldn't feel warmth, cold, or other sensations.</p> <p>Every square inch of skin contains thousands of cells and hundreds of sweat glands, oil glands, nerve endings, and blood vessels.</p> <h3>What Are the Parts of Skin?</h3> <p>Skin has three layers: the <strong>epidermis</strong> (ep-ih-DUR-mis), <strong>dermis</strong> (DUR-mis), and the <strong>subcutaneous</strong> (sub-kyoo-TAY-nee-us) <strong>tissue</strong>.</p> <p>The epidermis is the upper layer of skin. This tough, protective outer layer is thin in some areas and thick in others. The epidermis has layers of cells that constantly flake off and are renewed. In these layers are three special types of cells:</p> <ul class="kh_longline_list"> <li><strong>Melanocytes</strong> (meh-LAH-nuh-sites) make <strong>melanin</strong>, the pigment that gives skin its color. All people have roughly the same number of melanocytes; the more melanin made, the darker the skin. Exposure to sunlight increases the production of melanin, which is why people get suntanned or freckled.</li> <li><strong>Keratinocytes</strong> (ker-uh-TIH-no-sites) make <strong>keratin</strong>, a type of protein that's a basic component of hair, skin, and nails.&nbsp;Keratin in the skin's outer layer helps create a protective barrier.</li> <li><strong>Langerhans</strong>&nbsp;(LAHNG-ur-hanz) <strong>cells</strong> help protect the body against infection.</li> </ul> <p>Because the cells in the epidermis are completely replaced about every 28 days, <a href="">cuts and scrapes</a> heal quickly.</p> <p>Below the epidermis is the dermis. This is where our blood vessels, nerve endings, sweat glands, and hair follicles are. The dermis nourishes the epidermis. Two types of fibers in the dermis — <a href=""><strong>collagen</strong></a> and <strong>elastin</strong> — help skin stretch and stay firm.</p> <p><span style="font-size: 1em;">The dermis also contains a person's </span><strong style="font-size: 1em;">sebaceous</strong><span style="font-size: 1em;"> (sih-BAY-shiss) </span><strong style="font-size: 1em;">glands</strong><span style="font-size: 1em;">. These glands make the oil </span><strong style="font-size: 1em;">sebum</strong><span style="font-size: 1em;"> (SEE-bum), which softens the skin and makes it waterproof.</span></p> <p>The bottom layer of skin is the <strong>subcutaneous</strong> (sub-kyuh-TAY-nee-iss) <strong>tissue</strong>. It's made of connective tissue , blood vessels, and cells that store fat. This layer helps protect the body from blows and other injuries and helps hold in body heat.</p> <h3>What Does Hair Do?</h3> <p>The hair on our heads doesn't just look nice. It keeps us warm by preserving heat.</p> <p>Hair in the nose, ears, and around the <a href="">eyes</a> protects these sensitive areas from dust and other small particles. Eyebrows and eyelashes protect eyes by decreasing the amount of light and particles that go into them.</p> <p>The fine hair that covers the body provides warmth and protects the skin.</p> <h3>What Are the Parts of Hair?</h3> <p>Human hair consists of:</p> <ul> <li>the <strong>hair shaft</strong>, the part that sticks out from the skin's surface</li> <li>the <strong>root</strong>, a soft thickened bulb at the base of the hair</li> <li>the <strong>follicle</strong>&nbsp;(FAHL-ih-kul), a sac-like pit in the skin from which the hair grows</li> </ul> <p>At the bottom of the follicle is the<strong> papilla</strong>&nbsp;(puh-PILL-uh), where the actual hair growth happens. The papilla contains an artery that nourishes the root of the hair. As cells multiply and make keratin to harden the structure, they're pushed up the follicle and through the skin's surface as a shaft of hair.</p> <p>Each hair has three layers:</p> <ol> <li>the <strong>medulla</strong>&nbsp;(meh-DULL-uh) at the center, which is soft</li> <li>the <strong>cortex</strong>, which surrounds the medulla and is the main part of the hair</li> <li>the <strong>cuticle</strong> (KYOO-tuh-kull), the hard outer layer that protects the shaft</li> </ol> <p>Hair grows by forming new cells at the base of the root. These cells multiply to form a rod of tissue in the skin. The rods of cells move upward through the skin as new cells form beneath them. As they move up, they're cut off from their supply of nourishment and start to form a hard protein called keratin. This process is called <strong>keratinization</strong> (ker-uh-tuh-nuh-ZAY-shun). As this happens, the hair cells die. The dead cells and keratin form the shaft of the hair.</p> <p>Hair grows all over the human body except the palms of the hands, soles of the feet, and lips. Hair grows faster in summer than winter, and slower at night than during the day.</p> <h3>What Do Nails Do?</h3> <p>Nails protect the sensitive tips of fingers and toes. We don't need our nails to survive, but they do support the tips of our fingers and toes, protect them from injury, and help us pick up small objects. Without them, we'd have a hard time scratching an itch or untying a knot.</p> <p>Nails can be an indicator of a person's general health, and illness often affects their growth.</p> <h3>What Are the Parts of Nails?</h3> <p>Nails grow out of deep folds in the skin of the fingers and toes. As epidermal cells below the nail root move up to the surface of the skin, they increase in number. Those closest to the nail root get flat and pressed tightly together. Each cell becomes a thin plate; these plates pile into layers to form the nail.</p> <p>As with hair, nails form by keratinization. When the nail cells accumulate, the nail pushes forward.</p> <p>The skin below the nail is the <strong>matrix</strong>. The larger part of the nail, the <strong>nail plate</strong>, looks pink because of the network of tiny blood vessels in the underlying dermis. The whitish crescent-shaped area at the base of the nail is the <strong>lunula</strong>&nbsp;(LOON-yuh-luh).</p> <p>Fingernails grow faster than toenails. Like hair, nails grow faster in summer than in winter. A nail that's torn off will regrow if the matrix isn't severely injured.</p>La piel, el cabello y las uñasLa piel es nuestro órgano más grande. Si la piel de un varón adulto típico de 150 libras (68 kilogramos) fuera estirada, cubriría unas 2 yardas cuadradas (1,7 metros cuadrados) y pesaría unas 9 libras (4 kilogramos). La piel protege la red de músculos, huesos, nervios, vasos sanguíneos y todo lo que hay dentro de nuestro cuerpo. Nuestros párpados tienen la piel más fina y las plantas de los pies, la más gruesa.
Athlete's FootAlthough the name athlete's foot sounds funny, if you have this skin infection, you're probably not laughing. The good news is that it is generally easy to treat.
CellulitisCellulitis is an infection of the skin and underlying tissues that can affect any area of the body. It begins in an area of broken skin, like a cut or scratch.
DandruffIf you're worried about dandruff, you're not alone. Dandruff can start in puberty, and lots of teens and adults live with it. Learn how to control it.
Diaper RashDiaper rash is a very common infection that can cause a baby's skin to become sore, red, scaly, and tender. In most cases, it clears up with simple changes in diapering.
EczemaEverybody has dry skin once in a while, but eczema is more than just that. If your skin is dry, itchy, red, sore, and scaly, you may have eczema. Learn more about this uncomfortable condition and what you can to do stop itching!
Eczema (Atopic Dermatitis)Eczema can be an itchy nuisance and cause scratching that makes the problem worse. Many kids who have eczema today will be over it by the time they're teens.
Hives (Urticaria)Has your child broken out in welts? It could be a case of the hives. Learn how to soothe itchy bumps and help your child feel better.
ImpetigoImpetigo is a skin infection caused by fairly common bacteria. Read this article to learn how to recognize it and what to do about it.
Ingrown ToenailsA toenail is ingrown when it begins to break through and grow into the soft skin of the toe. Find out more about ingrown toenails.
Jock ItchJock itch is a pretty common fungal infection of the groin and upper thighs. It is generally easy to treat and prevent.
MelanomaMelanoma is different from other skin cancers because it can spread if it's not caught early. Find out how to lower your risk of getting melanoma and how doctors treat it.
ParonychiaParonychia is an infection of the skin around a fingernail or toenail. Most of the time, it's not serious. Find out what causes it, what to do, and how to prevent it.
RingwormRingworm isn't a worm at all - it's the name for a type of fungal skin infection. The good news is that ringworm is easy to treat.
ScabiesScabies is an infestation that affects the skin, and is caused by a mite that burrows into the top layer of skin. It causes itching and bumps or blisters.
Skin, Hair, and NailsOur skin protects the network of tissues, muscles, bones, nerves, blood vessels, and everything else inside our bodies. Hair and nails are actually modified types of skin.
VitiligoWhile vitiligo might make your child self-conscious, this skin condition is not medically dangerous. Kids with vitiligo are as healthy as other kids.
Your SkinNo matter how you think of it, your skin is very important. It covers and protects everything inside your body.
kh:age-allAgesOrAgeAgnostickh:clinicalDesignation-dermatologykh:genre-articlekh:primaryClinicalDesignation-dermatologyBody Basics Basics: Cancer Basics: Sports Medicine Basics: Cerebral Palsy