Histology of the Skin

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ANATOMY OF THE SKIN

• Dermatology—deals with the study of skin and its nature, structure, functions, diseases, and treatment

• Dermatologist—a physician engaged in dermatology

• Esthetician—a specialist in the cleansing, preservation of health, and beautification of the skin and body

HISTOLOGY OF THE SKIN

• Healthy skin– is slightly moist.– is soft and flexible.– has smooth and fine-

grained texture.– possesses slightly acid

reaction.

Appendages of the skin: Hair Nails Sweat and oil glands

The skin is the largest and one of the most important organs of the body.

HISTOLOGY OF THE SKINEpidermis• Outermost layer, commonly

called cuticle or scarf skin thinnest layer of skin; forms protective covering; contains no blood vessels

Dermis• Inner layer of skin, called

derma, corium, or true skin; about 25 times thicker than the epidermis and is highly sensitive

EPIDERMIS

• Stratum corneum—horny outer layer. Its scale-like cells are constantly shed and replaced. Cells contain protein keratin and combine with thin covering of oil to make the skin almost waterproof.

• Stratum lucidum—clear, transparent layer consisting of small cells through which light can pass.

EPIDERMIS• Stratum granulosum—granular layer in which

cells look like granules. Cells are almost dead and are pushed to the skin’s surface to replace those that are shed from the stratum corneum.

• Stratum germinativum—formerly known as stratum mucosum; deepest layer, responsible for growth of the epidermis; contains pigment called melanin, also found in hair. Pigment in this layer protects skin cells from ultraviolet rays by cells called melanocytes that produce melanin.

DERMIS• Papillary layer—lies directly beneath the

epidermis; contains small cone-shaped projections (called papillae) of elastic tissue that point upward to the epidermis. Some papillae contain looped capillaries. Others contain nerve fiber endings for the sense of touch called tactile corpuscles; contains melanin.

• Reticular layer—contains fat cells, blood and lymph vessels, sweat and oil glands, hair follicles, and arrector pili muscles. Supplies skin with oxygen and nutrients.

HOW SKIN IS NOURISHED

• Blood and lymph circulate through skin and contribute essential material for growth, nourishment, and repair of skin, hair, and nails.

NERVES OF THE SKIN• Motor nerve fibers—distributed to arrector pili muscles

• Sensory nerve fibers—react to heat, cold, touch, pressure, and pain; send messages to the brain; found in papillary layer; abundant in fingertips

• Secretory nerve fibers—distributed to sweat and oil glands; regulate excretion of perspiration and control flow of sebum to the surface of the skin

SKIN COLOR• Skin color depends on blood supply.

• Melanin, the pigment deposited inside the stratum germinativum and the papillary layer in the dermis.

• Hereditary traits vary among races and nationalities.

• Dark skin contains more melanin; light skin contains less.

STRENGTH and FLEXIBILITY

• Collagen– Fibrous protein that gives skin form and strength

• Elastin– Protein base that forms elastic tissue

GLANDS OF THE SKINSUDORIFEROUS GLANDS• Also called sweat glands• Have coiled base and tube-like duct to skin

surface• Are numerous on palms, soles, forehead, and

armpits• Regulate body temperature• Help eliminate waste• Eliminate 1 to 2 pints of salty liquid daily;

controlled by the nervous system

GLANDS OF THE SKINSEBACEOUS GLANDS• These are oil glands.• They are little sacs that open to skin’s

surface.• They secrete sebum.• They are found everywhere except on

palms and soles.• Sebum flows from ducts to follicles.• If duct is clogged, oil will harden and a

blackhead will form.

FUNCTIONS OF THE SKIN

PROTECTION - Injury - Bacteria

SENSATION - Heat - Touch - Pressure - Pain

HEAT REGULATION - Protects the body from environment

EXCRETION - Perspiration takes salt and other chemicals with it

SECRETION - Oil lubricates skin - Emotional stress will increase the flow

ABSORPTION - Limited but will absorb - Female hormones - Creams

FUNCTIONS OF THE SKINSENSORY NERVE ENDINGS OF THE SKIN

AGING OF THE SKIN• The sun• The environment• Health habits• General lifestyle

– Cigarette smoking has been linked to premature aging and wrinkling.

SUN AND ITS EFFECTS

SUN EFFECT• 80% to 85% of aging is caused by the

sun’s rays.• UVA rays

– Aging rays– 90% of sun’s ultraviolet rays

• UVB rays– Burning rays– Effects on melanocytes, cells that produce melanin

SUN AND ITS EFFECTSPRECAUTIONS• Wear protective lotion• Avoid sun exposure during peak hours• Apply sunscreen liberally after swimming• Avoid exposing children under six months• Wear hat and protective clothing outdoors

SKIN AGING AND THE ENVIRONMENT

ENVIRONMENTAL FACTORS• Pollutants from factories• Emissions from automobiles• Secondhand cigarette smoke

DEFENSE• Good daily skin care routine• Washing and exfoliating• Using moisturizers, protective lotions, foundation

DISORDERS OF THE SKIN• Primary lesions

(LEE-zhuns)– Bulla– Cyst– Macule– Papule– Pustule– Tubercle– Tumor– Vesicle– Wheal

DISORDERS OF THE SKIN• Secondary

lesions– Crust– Excoriation– Fissure– Keloid– Scale– Erosion– Ulcer

DISORDERS OF THE SKINSEBACEOUS (OIL)

GLANDS

• Comedone—blackhead; worm-like mass of hardened sebum in hair follicle

• Milia—whiteheads caused by accumulation of sebaceous matter beneath skin

DISORDERS OF THE SKIN

SEBACEOUS (OIL) GLANDS

• Acne—skin disorder characterized by chronic inflammation of the sebaceous glands from retained secretions

• Seborrhea—excessive secretion of sebaceousglands

DISORDERS OF THE SKINSEBACEOUS (OIL) GLANDS

• Asteatosis—excessive dryness; scaly skin; partial deficiency of sebum

• Rosacea—chronic congestion appearing primarily on the cheeks and nose

• Steatoma—tumor in the subcutanous tissue filled with sebum ranging in size from a pea to an orange

DISORDERS OF THE SKINSUDORIFEROUS (SWEAT) GLANDS

• Anhidrosis (an-hih-DROH-sis)—lack of perspiration, often a result of fever

• Bromhidrosis (broh-mih-DROH-sis)—foul smelling perspiration

DISORDERS OF THE SKIN• Hyperhidrosis (hy-per-hy-DROH-sis)—

excessive perspiration

• Miliaria rubra—prickly heat; an acute disorder characterized by eruption of small red vesicles resulting in burning and itching; caused by excessive heat

DISORDERS OF THE SKINSKIN INFLAMMATIONS

• Dermatitis—inflammatory condition of skin with lesions

• Eczema (EG- zuh-muh)—skin inflammation of acute or chronic nature, presenting many forms of dry or moist lesions; accompanied by itching or burning

DISORDERS OF THE SKIN

• Herpes simplex—recurring virus infection, commonly called fever blisters

• Psoriasis (suh-RY-uh-sis)—common, chronic, inflammatory skin disease found on scalp, elbows, knees, and chest

DISORDERS OF THE SKINOCCUPATIONAL DISORDERS• Abnormal conditions can result from contact with

chemicals or tints.

• Allergies can be developed to ingredients in cosmetics, antiseptics, perm solutions, and aniline derivative tints.

• These can cause dermatitis venenata–eruptive skin infections.

• To prevent, use rubber gloves and protective creams.

DISORDERS OF THE SKINPIGMENTATIONS OF THE SKIN• Lentigines—freckles; small yellow- to brown-colored

spots on parts exposed to sunlight and air• Leukoderma—abnormal white patches in the skin due

to congenital defective pigmentation• Nevus—birthmark• Stains—abnormal brown skin patches having a circular

or irregular shape; occur during aging, after certain diseases, and after disappearance of moles, freckles, and liver spots

DISORDERS OF THE SKINPIGMENTATIONS OF THE SKIN

• Tan—caused by exposure of the sun• Chloasma—increased deposits of pigment in

the skin; found mainly on forehead, nose, and cheeks; also called moth patches or liver spots

• Albinism—the absence of melanin pigment of the body, skin, hair, and eyes

• Vitiligo—acquired condition of leukoderma affecting skin or hair

DISORDERS OF THE SKINHYPERTROPHIES OF THE SKIN

• Keratoma—an acquired thickened patch of skin or epidermis due to pressure of friction on hands and feet. If it grows inward, it is called a corn.

• Mole—small, brownish spot or blemish on the skin, believed to be inherited; range in color from pale tan to brown to bluish black. Some are small and flat; others are raised and darker. DO NOT REMOVE HAIR FROM MOLES.

DISORDERS OF THE SKINHYPERTROPHIES OF THE SKIN

• Skin tag—small brown or flesh-colored outgrowth of the skin

• Verruca (vuh-ROO-kuh) or wart—caused by a virus and is infectious; can spread from one location to another, particularly along a scratch in the skin

DISORDERS OF THE SKINSKIN CANCER

• Basal cell carcinoma (kar-sin-OH-muh)

DISORDERS OF THE SKINSKIN CANCER• Squamous

(SKWAY-mus) cell carcinoma

• Malignant melanoma (mel-uh-NOH-muh)

MAINTAINING HEALTH OF THE SKIN

VITAMINS and SUPPLEMENTSVitamin A• Aids in health, function, and repair of skin cells• Is an antioxidant that can help prevent skin cancer• Can improve skin’s elasticity• Known as retinoic acid or Retin-A as a prescription

creamVitamin C• Needed for proper repair of skin and tissues• Speeds up healing process• Promotes collagen production

MAINTAINING HEALTH OF THE SKIN

VITAMINS and SUPPLEMENTS Vitamin D

– Promotes healthy skin– Promotes rapid healing of the skin

Vitamin E– Helps to heal damage to skin’s tissues– Topically, helps heal structural damage to skin

MAINTAINING HEALTH OF THE SKIN

VITAMINS and SUPPLEMENTS

Water• Composes 50% to 70% of body’s weight• Sustains health of the cells• Aids in elimination of toxins and waste• Helps regulate body’s temperature• Average person’s needs—8 to 10 (8 ounces) glasses of

water a dayDehydration• Slows metabolism• 75% of Americans chronically dehydrated

SKIN DISEASE DEFINITIONSdisease—any departure from normal state of health

acute disease—one with symptoms of a more or less violent character such as fever

chronic disease—one of long duration, mild but recurring

infectious disease—due to bacterial or viral germs resulting from contact with contaminated objects

contagious—communicable by contact

congenital—born with it

SKIN DISEASE DEFINITIONSseasonal—influenced by weather

occupational—due to certain kinds of employment that involve coming in contact with chemicals and the like

parasitic disease—one caused by parasites (ringworm)

pathogenic disease—produced by disease-causing bacteria (staph or strep viruses)

systemic—due to under- or overfunctioning of internal glands; may be caused by a faulty diet

venereal disease—contagious, caused by contact with an infected person during sexual intercourse

epidemic—simultaneously attacks a large number of people living in a particular locality (flu, smallpox)

allergy—a sensitivity to normally harmless substances such as cosmetics, medicines, tints, and certain foods

inflammation—characterized by redness, pain, swelling, or heat

SKIN DISEASE DEFINITIONS

SUMMARY• The skin is the largest organ of the body and protects us

from the environment.• It regulates body temperature and provides sensation.• Skin can be affected quite easily by most salon services.• It is important that you know what products can

penetrate the skin and what effects they will have on your clients.

• By learning to identify various diseases and disorders of the skin, you will be able to provide more effective and safe services for your clients.