Section 14.2 Your Skin, Hair, and Nails Objectives Identify the functions of the skin. Describe behaviors that can keep your skin healthy. Explain the functions of your hair and nails and how to care for them.

Myth Spending time in the sun can clear up acne. Fact Tanned skin may temporarily camouflage the redness of acne, but it does not treat the condition. Also, many acne medications make skin more sensitive to the sun. Identify another skin-care misconception that teens may hold. Why do you think they have that misconception?

Your Skin The skin covers and protects the body from injury, infection, and water loss. The skin also helps to regulate body temperature and gathers information from the environment. Protection The skin shields and protects the organs and tissues beneath it. Temperature Regulation When you are warm, sweat glands in the skin produce perspiration, which cools your body. When you are cold, the blood vessels narrow, keeping more heat within your body. Information Gathering Nerves in the skin provide information to your central nervous system about outside factors.

The Epidermis The outermost layer of your skin is the epidermis (ep uh DUR mis). The dead cells in skin contain a protein called keratin that makes the skin tough and waterproof. Cells deep in the epidermis produce the protein melanin, a dark pigment that gives skin some of its color.

The Dermis The dermis (DUR mis) is the tough, elastic layer of skin that lies below the epidermis. A tiny opening on the surface of the skin is called a pore. Strands of hair grow within the dermis in structures called follicles. Oil is secreted into follicles by sebaceous glands.

Layers of the Skin Sebaceous gland Hair Pore Epidermis Sweat droplet Fat Sweat gland Hair follicle Nerve Blood vessels Sweat droplet Pore Hair Sebaceous gland

Caring for Your Skin Eating a balanced, healthy diet; drinking plenty of water; and sleeping enough will keep your skin healthy. The most important things you can do for your skin are to avoid damage from the sun and tanning lamps and to monitor moles.

Preventing Skin Damage Overexposure to ultraviolet (UV) radiation can lead to skin cancer, including a sometimes deadly form called melanoma. When you are outside, it is important to wear sunscreen that blocks UVA and UVB rays. Sunscreen should be reapplied frequently.

Monitoring Moles The first sign of melanoma is usually an irregularly shaped mole, or brown spot, that increases in size. The mole may become blue-black or have blackish spots.

Treating Acne One common skin problem in teens is acne. Acne forms when excess oil and dead cells plug a hair follicle. Products that contain benzoyl peroxide can help mild cases of acne. A dermatologist is a doctor who specializes in treating skin problems.

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Treating Eczema Eczema (EK suh muh) is a condition in which an area of skin becomes red, swollen, hot, and itchy. Sometimes the skin blisters and oozes. In most cases, eczema can be treated with a medication applied to the skin.

Treating Skin Infections Boils Boils are swollen, painful infections of hair follicles caused by bacteria. Cold Sores Cold sores are clusters of watery blisters caused by a virus. Warts Warts are hardened growths on the skin that are also caused by a virus. Ringworm The ringworm fungus, which is highly contagious, produces red, scaly, ring-shaped patches on the skin. Athlete’s Foot Causes burning, itching, cracking, and peeling of the skin on the feet and between the toes.

Your Hair Hair protects the scalp from sunlight and provides insulation from the cold. Hairs in the nostrils and ears and your eyelashes, prevent debris from entering the body.

Care for Your Hair Frequent brushing of your hair will remove excess dirt and make your hair shine. Shampooing removes dirt and oil buildup from sebaceous gland secretions.

Hair Problems Head lice are small insects that live on the scalp and lay their eggs on hair. The best way to prevent infections is to avoid sharing combs, brushes, or hats. Dandruff occurs when the epidermal cells of the scalp are shed at a faster than normal rate. Some factors that may contribute to dandruff are fungal infections, overactive oil glands, stress, and heredity.

Your Nails Nails grow from an area of rapidly dividing cells near the tips of fingers and toes. The tough, platelike nails cover and protect the tips of your fingers and toes, which come in frequent contact with objects in your environment.

Caring for Your Nails Keeping your nails clean will help prevent the spread of infectious microorganisms to other parts of your body and to other people. Clip and file your nails so that their edges are smooth. Avoid biting your nails.

Nail Problems An ingrown toenail results when the sides of a toenail grow into the skin. If not treated properly, ingrown nails can become infected. Fungal infections of the nails are common in people who often have wet hands or feet. Infected nails appear thick and discolored with white markings.

Vocabulary epidermis The outermost layer of skin. keratin A protein in dead skin cells of the epidermis that makes skin tough and waterproof. melanin A pigment released in the epidermis that gives skin color and causes skin to tan. dermis A tough, elastic layer of skin that lies below the epidermis. pore A tiny opening in the skin through which sweat is secreted. follicle A skin structure in which a strand of hair grows and oil is secreted.

Vocabulary sebaceous gland A gland that secretes oil into a hair follicle in the skin; the oil softens and moistens hair and skin. melanoma A serious form of skin cancer. acne A lesion that forms when excess oil and dead cells plug a hair follicle. dermatologist A doctor who treats skin problems. eczema A condition in which an area of irritated skin becomes red, swollen, hot, and itchy.

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End of Section 14.2 Click on this slide to end this presentation.