By Neasia Clevenger

and Lysia Cook

The Skin

Definition• The thin layer of tissue forming the natural outer covering of

the body of a person or animal.• The skin is part of the integumentary system along with hair

and nails.• It is the largest organ in the body.

The Main Functions• It protects us from germs and the elements. • Is an aide in regulating body temperature.• Allows us to feel the sensations of touch, cold, and heat.

Other Uses• It absorbs the sun's ultra violet light to create small amounts of

vitamin D, which helps to build healthy bones and teeth.• When the skin gets wet, the first layer absorbs as much as it can

and wrinkles to preserve space.• if it did not wrinkle, your skin would expand too much and break open

The Layers Of The Skin

The 3 main layers of skin are the • Epidermis• Dermis• Hypodermis

The Epidermis• The epidermis is the outermost layer of skin which is made up

of dead cells. • This is the layer that can be seen by yourself and others.• It’s about as thick as a piece of paper, but thickens on the hands,

fingertips, and soles of the feet. • It supplies us with a waterproof barrier by absorbing water

when we touch it.

The Dermis• The dermis is the second layer of skin.• It has many fibers called collagen that provide strength and

allow skin in bend without tearing.• New skin cells are constantly being produced in this layer.• It contains the sturdy connective tissue, sweat glands, and hair

follicles.

The Hypodermis (Fat)• The hypodermis lies between the dermis and underlying tissues

and organs.• It’s made up of body fat and more connective tissue.• Acts as an energy and heat reserve for us.

Inside the Layers: Hair Follicles

• Hair follicles are the growth place of the hair on your body

• Every hair you have grows from a live follicle, with it’s root being in the hypodermis.

• They are connected to nerve endings, allowing you to sense the slightest touch.

Inside the Layers: Hair • Only your lips, soles of your feet, and

palms of your hands are really hairless.• The hair on our body acts as an insulator. • You get goose bumps when you’re cold

because the hair is rising and trying to form a barrier to trap warmer, still air next to your skin.

Inside the Layers: Sweat glands and Pores• Sweat glands secrete water, salt, and other waste products to

cool down the body as it evaporates.• You begin to sweat if you get too hot or if you’re stressed.• Sweat glands are all over your body, but are abundantly placed

on your palms, soles of feet, forehead, and underarms. • Apocrine glands are different from normal sweat glands and

give off an odor

Inside the Layers: Blood Vessels• Blood vessels help to keep your body at a regular temperature.• When the outside temperature drops, the vessels constrict

themselves to lessen the flow of blood to your skin, which keeps you warmer.

• As the outside temperature rises, the vessels dilate t help you keep cool.

Inside the Layers: Lymph Vessels• These vessels are a network similar to blood vessels, through

which lymph drains from the tissues and into the blood.• Lymph is a colorless fluid containing white blood cells that

bathes the tissue and acts as a cleanser.

Lymph Vessel

Inside the Layers: Sebaceous Glands• The sebaceous glands secrete sebum,

an oily substance that acts as a natural moisturizer and protective layer to your skin.

• The glands are mostly located near the base of hair follicles.

• These glands are the actual cause of acne. When the hair follicles get plugged with their oil, sebum, a pimple forms.

Inside the Layers: Keratinocytes • Keratinocytes are epidermal cells that produce keratin.• Keratin: A fibrous protein that gives are skin strength

Inside the Layers: Melanocytes• Melanocytes are the cells that absorb small

amounts of UV light to protect your skin.• They create melanin, which plays a role in

the color of your skin.• The more melanin you have, the more

melanocytes you have, which gives you more protection from the sun.

Why are you the color you are?• Melanocytes: a cell in the layer of the epidermis that produces

melanin • Melanin is the thing that gives you the pigment you have.• The more melanin, the darker your skin and hair.• Your color, or the amount of melanocytes, you’ll have are

determined by your parents traits and backgrounds.

Sensory Reception• The skin is filled with sensory receptors that sense pain, heat,

cold, touch, and pressure.• The number of skin receptors vary in number all over the body.• For example, the hands have less receptors for temperature than

the head.• Nerves travel through out your body and, in the skin, are

attached to hair follicles in and throughout the dermis.

Video• http://www.youtube.com/watch?v=yKAzVC0WcmI

How to Care for Your Skin• Protect yourself from the sun.

• Limit the time you take to bathe, avoid strong soaps, and shave carefully.

• Eat a healthy diet.

• Don’t smoke, although this doesn’t apply to people are age, it can cause serious effects on our skin.

• Managing stress.

Sun Damage• Ultra violet sun rays penetrate deeply in your skin and kill

living cells.• Excessive tanning can damage skin by causing

• Freckles• Sunspots• Age spots• Skin cancer

• Thinking you have a natural tan (not caused by a tanning bed) will protect you from sun exposure is actually wrong.• A natural tan is equivalent to an SPF of 4.

• The reason that sunburn is red is because blood flow is increased and sent to the burned areas, making it read and warm to the touch.

Hygiene • Don’t take excessively long showers often.• Avoid powerful soaps.

• Doing these things can strip your skin of natural oils in needs and make it dry out.

• Shave carefully and in the direction the hair grows.• Pat dry after showers to allow some moisture to be held by the

skin.• Doing these things will ensure your skin stays moisturized and is still

clean.

Eat a Healthy Diet• Eating fruits, vegetables, whole grains, and lean proteins has

been thought to decrease the amount of acne you have.• A diet high in vitamin C and low in unhealthy fats and

processed/refined carbohydrates will promote younger looking skin.

• Eating healthy will simply make you look and feel better.

Don’t Smoke• Smoking causes the tiny blood vessels in the out layer of our

skin to narrow.• As they become narrow, the skin is deprived of oxygen and

nutrients that are important in having healthy skin.• Smoking also damages elastin and collagen, which are the

fibers that give your skin strength and elasticity.• Even being exposed to second hand smoke can be damaging.

Manage Your Stress• Constant stress can make your skin more sensitive and more

prone to acne breakouts.• It is important to have a healthy state of mind by taking steps to

manage stress.• Setting reasonable limits and not taking on more than you can

accomplish are easy ways to do so.

Review Worksheet: Students come up and put the answers they got.

Worksheet Answer Key

Epidermis

Dermis

Blood & Lymph Vessels

Hypodermis

Hair FollicleSweat Gland

Sebaceous Gland

Melanocytes & Keratinocytes Pore

Bibliography• Allen, Katy Z. Human Body Systems and Health. Austin, TX: Holt,

Rinehart, and Winston, 2005. Print.• Colombo, Luann. Uncover the Human Body. San Diego, CA: Silver

Dolphin, 2002. Print.• "Get Inside Your Skin." WebMD. WebMD. Web. 05 May 2012.

<http://www.webmd.com/healthy-beauty/healthtool-inside-your-skin>.• Rooney, Anne. Human Body Works: The Nervous System, the Skin, the

Senses. Chicago: World Book, 2007. Print.• "The Skin (Human Anatomy): Picture, Definition, Function, and Skin

Conditions." WebMD. WebMD. Web. 05 May 2012. <http://www.webmd.com/skin-problems-and-treatments/picture-of-the-skin>.

• Staff, Mayo Clinic. "Skin Care: 5 Tips for Healthy Skin." Mayo Clinic. Mayo Foundation for Medical Education and Research, 06 Dec. 2011. Web. 05 May 2012. <http://www.mayoclinic.com/health/skin-care/SN00003>.

• "Touch." ThinkQuest. Oracle Foundation. Web. 05 May 2012. <http://library.thinkquest.org/05aug/00386/touch/sensoryreceptors.htm>.