1. By Neasia Clevenger and Lysia Cook
The Skin
By Neasia Clevenger
and Lysia Cook

2. 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.

3. 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.

4. 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

5. The Layers Of The Skin The 3 main layers of skin are the Epidermis
Hypodermis

6. 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.

7. 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.

8. 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.

9. 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.

10. 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.

11. 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

12. 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.

13. 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

14. 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.

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

16. 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.

17. 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.

18. 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.

19. Video

20. 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.

21. 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.

22. 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.

23. 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.

24. 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.

25. 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.

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

27. Worksheet Answer Key Pore Melanocytes & Keratinocytes Sebaceous Gland
Epidermis
Dermis
Blood & Lymph Vessels
Hypodermis
Hair Follicle
Sweat Gland

28. Bibliography
Allen, Katy Z. Human Body Systems and Health. Austin, TX: Holt, Rinehart, and Winston, Print.
Colombo, Luann. Uncover the Human Body. San Diego, CA: Silver Dolphin, Print.
"Get Inside Your Skin." WebMD. WebMD. Web. 05 May <
Rooney, Anne. Human Body Works: The Nervous System, the Skin, the Senses. Chicago: World Book, Print.
"The Skin (Human Anatomy): Picture, Definition, Function, and Skin Conditions." WebMD. WebMD. Web. 05 May <
Staff, Mayo Clinic. "Skin Care: 5 Tips for Healthy Skin." Mayo Clinic. Mayo Foundation for Medical Education and Research, 06 Dec Web. 05 May <
"Touch." ThinkQuest. Oracle Foundation. Web. 05 May <