Warm Up

• As a group, complete the concept map on chart paper.

Integumentary System

McDougal/Littel

Skin Performs Important Functions

• Includes skin, hair, and nails.

• Functions:– Skin repels water.– Skin guards against infection.– Skin helps maintain

homeostasis.– Skin senses the

environment.

The structure of skin is complex.

EpidermisEpi- above/uponOuter layer• The cells of the

epidermis contain many protein fibers that give the skin tough, protective qualities.• Waterproof layer

about 30 cells deep.

DermisDerma-skin

Inner layer• Strong and elastic. • Changes shape to prevent

tearing• Rich in blood vessels (02 )• Fatty tissue ; protects the

body from extremes in temperature, stores energy

• Includes sweat and oil glands, hair, nails, and sensory receptors.

Sweat and Oil Glands

• Sweat glands help control body temperature,• Oil glands protect the skin by keeping it moist. • Both types glands open to the surface through

tiny openings in the skin called pores.• Pores allow important substances to pass to

the skin’s surface.• Pores can become clogged with dirt and oil.

Keeping the skin clean can prevent blockages.

How Do These Glands Maintain Homeostasis ?

You Try• Rub a cotton ball dampened with

alcohol across one of your palms.• Alcohol removes the oil from the

surface of your skin.• Drip a couple of drops of water onto

the palm with alcohol. • Observe what happens. • Record your observations.• Drip a couple of drops of water onto

your other palm.• Observe what happens. • Record your observations.

Hair and Nails

• Many cells in your hair and nails are dead but continue to perform important functions.

• Hair – Shields your head from the Sun. – In cold weather, it traps heat close to your

head to keep you warmer. • Fingernails and toenails – protect the tips of the fingers and toes from

injury.

Sensory Receptors

• These receptors are part of the nervous system located in your skin.

• Your skin contains receptors that sense– heat – cold– pain – touch– pressure

• These sensors help protect the body.

Sense

• List words associated with the term sense.• 1.• 2.• 3.• 4.• 5.

The Skin Grows and Heals

• Most of the growth of your skin occurs at the base of the epidermis just above the dermis.

• The cells there grow and divide to form new cells, constantly replacing older epidermal cells as they die and are brushed off during daily activity.

• Which process involves the growing and dividing of new cells?

Injuries and Healing

• Injuries to your skin may include blisters, burns, cuts, and bruises.

• Most such injuries result from the skin’s contact with the outside world, such as a concrete sidewalk.

• In simple injuries, the skin can usually repair itself.

Burns

• Burns can be serious injuries caused by heat, electricity, radiation, or certain chemicals.

• In mild cases—those of first-degree burns—skin merely becomes red, and the burn heals in a day or two.

• In severe cases—those of second-degree and third-degree burns—the body loses fluids, and death can result from fluid loss, infection, and other complications.

• http://www.classzone.com/books/ml_science_share/vis_sim/hbm05_pg87_skin/hbm05_pg87_skin.html

Damage to Skin/Protection

• Sunburns – Repeated burning can

increase the chance of skin cancer.

• Frostbite– extreme cases,

frostbitten limbs become diseased and have to be amputated.

• Good nutrition• Appropriate

coverings• Cleanliness

Artificial Skin• To make artificial skin, scientists start with cells in a tiny

skin sample. • Cells from infants are used because infant skin-cell

molecules are still developing, and scientists can manipulate the molecules to avoid transplant rejection.

• The cells from just one small sample of skin can be grown into enough artificial skin to cover 15 basketball courts.

• Before artificial skin, badly burned victims didn’t have much chance to live.

• Today, 96 out of 100 burn victims survive.

What the Functions of the Skin?

• Create a Venn diagram comparing the functions of the dermis and the epidermis.