The SkinBy: Veronica Martinez and Paola Rios

Health Class Spartans 2014

The skin is the largest organ of your body. It is part of the integumentary system,

which includes all the external coverings of your body, like skin, nails, and hair.

Functions of the skin:What is the skin?

Skin covers your bones and muscles and protects them from the external environment.

It keeps your body from drying out in the sunlight and wind.

It also protects the cells and tissues under the skin.

Is the first line of defense against dirt, bacteria, and viruses that might enter your body.

Functions of the skin:Protection

• The skin has special sensory receptors that detect texture.

• It also detects temperature and senses pain.

• The more sensory receptors in one area the more sensitive it is.

Functions of the skin: Sensory Response

Skin helps control body temperature. Sweating is one way skin lowers your

body temperature. As sweat evaporates, excess thermal energy leaves the body and skin cools.

Another way is by releasing thermal energy from blood vessels, which is why your face turns red while exercising.

This happens because blood vessels enlarge.

Functions of the skin: Temperature Regulation

When your skin is exposed to sunlight it can make vitamin D.

Your body needs vitamin D to help it absorb calcium and phosphorous and promote the growth of bones.

Vitamin D is usually added to milk and is found in some types of fish.

Functions of the skin:Production of vitamin D

Normal cellular processes produce waste products and the skin eliminates these wastes.

Water, salts, and other waste products are removed through the pores.

You might notice when you sweat.

Functions of the skin:Elimination

Instructions: Touch the back of your hand with an ice

cube in a plastic bag. Now do the same to the back of your knee.Questions: Which area was more sensitive to cold?How do you think the skin senses

temperature?How does sensitivity to temperature protect

the body?

Activity#1: How does your skin protect your body?

Instructions: Put on one plastic bag in your hand. Leave it on for about 5 min.Questions: What happened inside the bag? What might have caused this?

Activity #2:Why are you sweating?

Is the outmost layer of skin and the only one who comes in contact with the outside environment.

Is thin but tough. The epidermis on your eyelids in thinner than a sheet of paper.

The epidermis cells are constantly shed and replaced. Epidermis produces melanin. Melanin is a pigment that protects the body by absorbing some of the Sun’s damaging ultraviolet rays.

Structures of the skin:Epidermis

The dermis is a thick layer of the skin that gives skin strength, nourishment, and flexibility.

It contains sweat glands, blood vessels, nerves, hair follicles, and muscles.

When the muscles in the dermis contract, you get goose bumps.

Structures of the skin: Dermis

The innermost layer of skin insulates the body, acts as protective padding, and stores energy.

It is sometimes called fatty layer. It can be very thin or very thick, depending on its location on the body.

Structures of the skin:Fatty Layer

A bruise is an injury where your blood vessels in the skin are broken, but the skin is not cut or opened.

The broken blood vessels release blood into the surrounding tissue, they change color as they heal.

Skin injuries and repair:Bruises

When you break one or more layers of skin, it is called a cut.

The blood you release will usually thicken and form a scab over the cut.

The scab prevents outside substances from entering the body.

Skin heals by producing new skin cells that repair the cut.

Some cuts are too large to heal, if that happens you may need to get stitches.

Skin injuries and repair: Cuts

Burns do not only occur by touching hot objects.

Burns can also be caused by touching extremely cold objects, chemicals, radiation, electricity, or friction.

There are degrees of burns.

Skin injuries and repair:Burns

Degrees of burns: First Degree

Burn Symptoms

First degree burn • Damages top layer of skin

• Symptoms:Pain, redness, swelling• Usually heals in 5-7

days without scarring

Burn Symptoms

Second Degree Burn • Damages top two layers of skin

• Symptoms: Pain, redness, swelling, blistering

• Usually heals in 2-6 weeks with some scarring

Degrees of burns:Second Degree

Burn Symptoms

Third degree burn • Damages all three layers of skin and sometimes the tissue below skin

• Symptoms: black or white charred skin, may be temporarily numb due to damaged nerves

• Heals over months with scarring; might require surgery

Degrees of burns: Third Degree

One important thing you can do for your skin is protect it from sunlight.

By using sunscreen and protective clothing and avoid outside activities during the middle of the day you can protect your skin.

The rays of sunlight can cause permanent damage to the skin, including wrinkles, dry skin, and skin cancer.

You can keep your skin healthy by eating a balanced diet.

You can also apply lotion to your skin to keep it moist and use gentle soap to clean it.

Healthy skin

Homeostasis is an organism’s ability to maintain steady internal conditions when outside conditions change.

Skin also works with other body systems to maintain homeostasis.

Circulatory system: helps cool the body when it becomes overheated.

Nervous and muscular systems: help the body react to stimuli.

The Skin and Homeostasis and other systems

Reaction to stimuli

Go back to activity 2

Information and photos: Science Book www.beltina.org

Bibliography