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Section 14.2 Your Skin, Hair, and Nails

Slide 1 of 26

• The skin covers and protects the body from injury,

infection, and water loss.

Your Skin

• 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.


Slide 2 of 26

• The outermost layer of your skin is the epidermis

(ep uh DUR mis).

The Epidermis

• 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.


Slide 3 of 26

• The dermis (DUR mis) is the tough, elastic layer of

skin that lies below the epidermis.

The Dermis

• 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.


Slide 4 of 26

Layers of the Skin

Epidermis

Dermis

Fat

Sweat

gland Hair follicle Nerve

Blood vessels

Sweat

droplet

Pore Hair

Sebaceous

gland


Slide 5 of 26

• Eating a balanced, healthy diet; drinking plenty of

water; and sleeping enough will keep your skin

healthy.

Caring for Your Skin

• The most important things you can do for your skin

are to avoid damage from the sun and tanning lamps

and to monitor moles.


Slide 6 of 26

• Overexposure to ultraviolet (UV) radiation can lead

to skin cancer, including a sometimes deadly form

called melanoma.

Preventing Skin Damage

• When you are outside, it is important to wear

sunscreen that blocks UVA and UVB rays.

• Sunscreen should be reapplied frequently.


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• The first sign of melanoma is usually an irregularly

shaped mole, or brown spot, that increases in size.

Monitoring Moles

• The mole may become blue-black or have

blackish spots.


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• One common skin problem in teens is acne.

Treating 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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• Eczema (EK suh muh) is a condition in which an area

of skin becomes red, swollen, hot, and itchy.

Treating Eczema

• In most cases, eczema can be treated with a

medication applied to the skin.

• Sometimes the skin blisters and oozes.


Slide 13 of 26

• Boils Boils are swollen, painful infections of hair follicles

caused by bacteria.

Treating Skin Infections

• Warts Warts are hardened growths on the skin that are also

caused by a virus.

• Cold Sores Cold sores are clusters of watery blisters 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.


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• Hair protects the scalp from sunlight and provides

insulation from the cold.

Your Hair

• Hairs in the nostrils and ears and your eyelashes,

prevent debris from entering the body.


Slide 16 of 26

• Frequent brushing

of your hair will

remove excess dirt

and make your

hair shine.

Care for Your Hair

• Shampooing

removes dirt and

oil buildup

from sebaceous

gland secretions.


Slide 17 of 26

• Head lice are small insects that live on the scalp and

lay their eggs on hair.

Hair Problems

• 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.


Slide 18 of 26

• Nails grow from an area of rapidly dividing cells near

the tips of fingers and toes.

Your Nails

• The tough, platelike nails cover and protect the tips

of your fingers and toes, which come in frequent

contact with objects in your environment.


Slide 19 of 26

• Keeping your nails

clean will help prevent

the spread of infectious

microorganisms to

other parts of your body

and to other people.

Caring for Your Nails

• Clip and file your nails

so that their edges

are smooth.

• Avoid biting your nails.


Slide 20 of 26

• An ingrown toenail results when the sides of a

toenail grow into the skin.

Nail Problems

• 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.


Slide 21 of 26

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.


Slide 22 of 26

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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