Title: All about the skin

In order to care for the skin it is important to know a bit about the skin and it's different layers.

This lesson is all about the different layers of the skin along with the function of the skin.  You will be lead through some videos, written information, and a few multiple choice questions, just to make sure your catching the important stuff

Let's start with the basic function of the skin.

Please get your textbook and turn to page 601 for additional help through this lesson.

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The Purpose of the Skin

Your textbook does an excellent job explaining the purposes of the skin on Page 614.  Please refer to that as needed.  Below is a brief summary of the purpose of the skin:

Protection:  Can you imagine if we didn't have any skin?  What would be there to protect the inside of our bodies.  Think of our skin as our bodies raincoat.

Sensation:  Your skin provides you with the ability to feel.  Without the ability to feel you would never know when something was too hot to touch.  Imagine the injuries that you would have.

Heat Regulation:  Your skin has an amazing ability to keep you warm when the outside is cool and to keep you cool when the outside is warm.  When it is warm out your body sends blood to the skin to cool off (this is why when your skin gets red when it is warm, it is your skin trying to cool you off).  When it is cold outside your skin turns white because your body is sending your blood further into your body to keep you warm.

Excretion: This is your ability to sweat which is part of heat regulation but when you sweat you also excrete water and salt, they exit your body.

Secretion: This has to do with the oil that your body releases that keeps your skin soft and pliable.  The oil that the skin releases also helps to keep the hair soft.

Absorbtion:  Think about when you put lotion on your hands and face how it is absorbed by the skin,  or if you have ever needed a medicinal cream for a rash, your skin can absorb some medical ingredients too.

Ok, that is a lot about the function of the skin but it is a pretty amazing organ.  The largest organ in the body, in fact.  And if you break that down into 6 different functions it really isn't that bad.

Q: Why is your skin like a raincoat?
- It is waterproof. (correct)
- It is yellow like some people's skin
- It is rubbery.

Q: What do the nerve endings in your skin help you to do? Click all that apply.
- Pull your hand away when it touches a hot stove. (correct)
- Makes your skin feel itchy.
- Make your skin soft.

Q: Why does your skin turn red when you are hot?
- Your blood is coming to the surface of the skin to cool your body off. (correct)
- Your white blood cells are going further into the body leaving your skin to look more red.

Q: Why does your skin turn white when you are cold?
- Your blood is going further into your body to keep your core warm. (correct)
- Your white blood cells are coming to the surface to keep your body warm.

Q: What does your body excrete when it sweats?
- water and salt (correct)
- water
- oil and water

Q: Why does your body sweat?
- To cool your body down. (correct)
- To make sure you know when you have been working hard.

Choose the correct statements.

- The oil the skin secretes helps keep the skin from cracking. (correct)
- The oil the skin secretes helps cool the body down.

- The oil the skin secretes coats the hairshaft and skin. (correct)
- The oil the skin secretes only coats the skin.

Q: True or false, the skin will absorb lotion.
A: true
If wrong: Think about when you apply sunscreen. Does it stay white and on top of your skin or does it soak into your skin?

Q: What can you do to maintain healthy skin?
- Drink 8 glasses of water a day. (correct)
- Wear make-up.
- Wear sunscreen. (correct)
- Stay out of the direct sunlight as much as possible. (correct)

Choose the correct statement.

Watch the above video about the different layers of the skin.  You don't have to memorize everything in the video as you watch it but it will give you the opportunity to hear the terms used when talking about the skin.

There are three different layers of the skin that we will look at more indepth:  The Epidermis, The Dermis, and the Subcutaneous Tissue or fatty layer.

Q: Why did they refer to the epidermis as a skin graveyard?
- Because when the skin cells reach the surface of the skin they are no longer living. (correct)
- Because the skin is not a living organ.
- Because dry skin can feel like a desert.

Q: How long does it take skin cells to reach the top layer of skin once they are formed?
- About 4 weeks. (correct)
- About 1 week.
- About 2 weeks
- About 3 weeks

Q: What is the name of the pigment found in the skin?
- Melanin (correct)
- Gelatin
- Cortex

Q: Which of the following is NOT a function of melanin?
- Keeps the skin soft and pliable. (correct)
- Gives us our skin color.
- Protects our body from the sun.

Q: What substance comes out of skin pores?
- Sweat (correct)
- Oil

Q: How does sebum (oil) benefit the skin?
- Creates a waterproof barrier. (correct)
- Protects from the sun.

Q: Nerve endings in the skin are responsible for what sensations?
- All options are correct. (correct)
- Heat
- Cold
- Tickling

- Epidermis
- Dermis
- Subcutaneous Tissue
- [Image: Skin]
Q: Top Skin Layer
Q: Middle Skin Layer
Q: Bottom Skin Layer

Choose the correct statement.

Drag the words into the boxes with the correct definitions.

Q: The [...] is the see through layer of the epidermis. The
[...] is the top layer of skin composed of mostly dead skin cells. The [...] is the layer of skin has flat skin cells waiting to be pushed to the top. The [...] is the bottom layer of the epidermis and contains the skin's melanin. The [...] is also where all of the skin cells are produced.
A: stratum lucidum; stratum corneum; stratum granulosum; stratum germinativum; stratum germinativum

Choose the correct statement.

The Epidermis is the outermost layer of the skin, the thinnest layer of the skin, and it contains no blood but many small nerve endings.

Essentially there are four different layers in the epidermis.

Stratum Corneum:  This is the top layer that is constantly being replaced.  When you scratch or rub your skin you are loosing many dead skin cells from this layer.  But not to worry there is a layer underneath waiting to come to the top to replace those cells that are constantly being shed.

The Stratum Corneum is also the layer of the skin that makes it water proof.  The keratin cells mix with a thin layer of oil and voila! you have a water proof layer.

If you want to try to remember this layer, I try to think of it like corn meal (you know corneum) and it is kind of dead and flakey like corn meal  Come on work with me here!

Stratum Lucidum:  What comes to mind when you think of something as lucid?  See through right?  Well that is exactly what this layer is; a see through layer of small cells.  If we are using food as our way to remember this layer then I guess this layer would be like honey or oil.

Stratum Granulosum: These are flat cells that are almost dead and they are just waiting to be pushed to the top layer to replace the cells that have been shed from rubbing or scratching the stratum corneum (the top layer remember).  I picture this layer to be like Special K cereal or something flat like that.

Stratum Germinativum:  What do you think of when you think of the word germinativum?  Germinate, right?  And what does it mean to Germinate?  It means to grow.  This is the layer where the cells are being made that eventually go to the top layer and are then shed.  I like to think of this layer as the Chocolate Rice Krispie layer.  The cells are fairly round, at least not squished like the layer above (the stratum granulosum), and they are darker because this is the layer that has the melanin that determines skin color.

- [Image: Epidermis]
- Stratum Lucidum
- Stratum Corneum
- Stratum Germinativum
- Stratum Granulosum
Q: First Layer
Q: Layer 2
Q: Third Layer
Q: Bottom Layer

The Dermis Is Under the Epidermis

The next layer down is the dermis (say: dur-mis). You can't see your dermis because it's hidden under your epidermis. The dermis contains nerve endings, blood vessels, oil glands, and sweat glands. It also contains collagen and elastin, which are tough and stretchy.

The nerve endings in your dermis tell you how things feel when you touch them. They work with your brain and nervous system, so that your brain gets the message about what you're touching. Is it the soft fur of a cat or the rough surface of your skateboard?

Sometimes what you feel is dangerous, so the nerve endings work with your muscles to keep you from getting hurt. If you touch something hot, the nerve endings in your dermis respond right away: "Ouch! That's hot!" The nerves quickly send this message to the brain or spinal cord, which then immediately commands the muscles to take your hand away. This all happens in a split second, without you ever thinking about it.

Q: The inner layer of skin containing the hair follicles,papillae, nerve endings, and capillaries is known as:
- Dermis (correct)
- Epidermis
- Subcutaneous Tissue

Q: The nerves in your skin send messages to the ______________________ so that you understand what you are touching.
- brain (correct)
- hands
- heart

Click here for multiple choice quesions ------>>>

Click here for picture of the dermis ------------>>>

[Image: Dermis]

Dermis = Lots of Blood Vessels

Your dermis is also full of tiny blood vessels. These keep your skin cells healthy by bringing them the oxygen and nutrients they need and by taking away waste. These blood vessels are hard to see in kids, but you might get a better look if you check out your grandparents' skin. As the dermis gets older, it gets thinner and easier to see through.

The dermis is home to the oil glands, too. These are also called sebaceous (say: sih-bay-shus) glands, and they are always producing sebum (say: see-bum). Sebum is your skin's own natural oil. It rises to the surface of your epidermis to keep your skin lubricated and protected. It also makes your skin waterproof — as long as sebum's on the scene, your skin won't absorb water and get soggy.

You also have sweat glands on your epidermis. Even though you can't feel it, you actually sweat a tiny bit all the time. The sweat comes up through pores(say: pors), tiny holes in the skin that allow it to escape. When the sebum meets the sweat, they form a protective film that's a bit sticky.

An easy way to see this film in action is to pick up a pin with your fingers. Then wash your hands well with soap and water and dry them off completely. Now try to pick up that pin again. It won't be so easy because your sticky layer is gone! Don't worry — it will be back soon, as your sebaceous and sweat glands create more sticky stuff.

http://kidshealth.org/kid/htbw/skin.html#

[Image: Sensory Nerves]

[Image: Skin Glands]

<--------picture of nerve   picture of glands ------->

Subcutaneous Fat

The third and bottom layer of the skin is called the subcutaneous (say: sub-kyoo-tay-nee-us) layer. It is made mostly of fat and helps your body stay warm and absorb shocks, like if you bang into something or fall down. The subcutaneous layer also helps hold your skin to all the tissues underneath it.

This layer is where you'll find the start of hair, too. Each hair on your body grows out of a tiny tube in the skin called a follicle (say: fah-lih-kul). Every follicle has its roots way down in the subcutaneous layer and continues up through the dermis.

You have hair follicles all over your body, except on your lips, the palms of your hands, and the soles of your feet. And you have more hair follicles in some places than in others — there are more than 100,000 follicles on your head alone!

Your hair follicles rely on your sebaceous glands to bring on the shine. Connected to each follicle in the dermis layer is a tiny sebaceous gland that releases sebum onto the hair. This lightly coats the hair with oil, giving it some shine and a little waterproofing.

http://kidshealth.org/kid/htbw/skin.html#

[Image: Subcutaneous Fat]

Click here for multiple choice questions.

<----------

Q: The fatty layer underneath the dermis is called:
- Subcutaneous tissue (or subcutaneous fat) (correct)
- Epidermis
- Stratum lucidum

Q: What is the purpose of the subcutaneous fat?
- It helps keep your body stay warm and absorbs shock. (correct)
- It keeps the elasticity of the skin.
- It maintains the shine to the skin.

Q: True or false, you have hair follicles all over your body, except on your lips, the palms of your hands, and the soles of your feet.
- True (correct)
- False

The skin is nourished the same as every other cell in the body is nourished.  It is nourished through the blood and lymph.  The blood and lymph circulate essential nutrients to the cells in the body.

It stands to reason then that if you are not healthy or getting enough nutrients, then your blood and lymph are not getting enough nutrients, and therefore your skin is not getting enough nutrients.  That is one of the reasons that your skin can show your health.  If your skin is healthy it means that the rest of your body has the proper nutrients to feed it, so it will look plump, pliable, and slightly pink.

If you want your skin to look good one of the first places to start is by eating well and staying healthy.

Q: What two bodily fluids bring nutrients to the skin?
- blood and lymph (correct)
- blood and urea
- plasma and lymph
- blood and water

Q: Nerve fibers which react to heat, cold, touch, pressure, and pain are the:
- sensory nerve fibers (correct)
- secretory nerve fibers
- excretory nerve fibers
- motor nerve fibers

Q: Nerve fibres which are distrubuted to the arrector pilli muscles attached to hair follicles and are responsible for goose bumps are called:
- Motor nerve fibres (correct)
- sensory nerve fibers
- secretory nerve fibers
- excretory nerve fibers

Q: Nerve fibers which are distributed to the sweat and oil glands of the skin and regulate the excretion of perspiration and control the flow of sebum to teh skin surface are the:
- secretory nerve fibers (correct)
- motor nerve fibers
- sensory nerve fibers
- excretory nerve fibers

Q: The skin contains two types of glands, they are:
- sweat and oil glands (correct)
- lymph and sweat glands
- lymph and oil glands

Q: Which of the following below is not a function of the sweat glands?
- lubricates the skin (correct)
- cools down the skin
- releases water
- releases salt

Q: Where are the oil glands located?
- they are attached to the hair follicle (correct)
- they have a coil base that ends at the skin surface
- they are within the subcutaneous tissue

Q: What is the purpose of the oil glands?
- to lubricate the skin and keep the hair soft (correct)
- to cool the body down
- to eliminate waste products from the body

Choose the correct statement.

- Melanin is responsible for the color of our skin. (correct)
- The dermis is responsible for the color of our skin.

There are a lot of technical terms in this video.  Don't worry, you don't have to memorize them.  Just focus on the bigger concept of why we have different colors of skin.  Melanin is the key word to know here.

Q: True or False, UV light can cause damage to the DNA in our skin.
- True (correct)
- False

Q: The melanin is contained in what layer of the skin?
- Epidermis (correct)
- Dermis
- Subcutaneous Tissue

Q: True or False, UV radiation causes your skin to appear tanned.
- True (correct)
- False

Choose the correct statement.

- Melanin is responsible for the color of our skin. (correct)
- The dermis is responsible for the color of our skin.