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2. Integumentary System the WHAT? That stuff! Your SKIN!

3. Review Time! • Structure = a part of the body • Function = a job to do • Homeostasis = balance in the body • Stimulus = something the body senses • Response = how the body reacts to the stimulus …yeah…can’t wait for the DISORDERS, too

4. (your skin grows as you do…and if you become dramatically smaller, you’ll be left with your full-sized organ)! #1 Integumentary System Overview Do you ever think of your skin as an organ? Probably not very often, if ever. But it IS an organ, and one of your largest! Take your skin off, and you’d weigh 5 to 10 pounds less, but more importantly, you wouldn’t last very long.

5. #2 Integ. Sys. Overview, contd. Your skin has a BRUTAL job. It’s your only major organ on the OUTSIDE of your body, so it has to deal with conditions that would totally overwhelm your heart or kidneys or any other organ. Because of this constant attack, your skin cells die & are replaced every month! Your integumentary system is any surface covering for the body. We’ll focus on the major ones (skin, hair, nails). Technically, your integumentary system also deals with the tissues that line the inside of your organs—like the lining of your throat down your esophagus, and so forth. But we’ll focus on your outside skin this year. Let’s see what your skin does for ya…

6. #3 FUNCTIONS of the Integumentary System 1. protection from environment & germs 2. regulates body temperature 3. excretes (gets rid of) wastes in sweat 4. has nerves to sense environment 5. produces vitamin D in sunlight wow! (vitamin D is vital in helping your bones absorb calcium)

7. #4 Functions, contd. Those are some very important functions, eh? Now, let’s see the structures that make all these functions happen. There’s a lot—be warned!

8. fatty layer #5 STRUCTURES of the Integumentary System Your skin is the largest organ of the body. It has a lot of important jobs, which we just saw, and is made of two main layers: • epidermis – this is the thin outer layer of constantly • replaced dead cells. • The epidermis is • the body’s barrier • to the outside world. • dermis – this is the • thicker inner layer • containing the • following structures:

9. #6 Structures in the Dermis i. sweat gland –excretes waste & cools body ii. sebaceous (oil) gland. you need SOME oil on your skin to keep it healthy. iii. hair follicles which poke up out of the surface of the skin iv. blood vessels including small arteries, veins & capillaries (are you writing these structures in the blanks on the back of your page?)

10. #7 Structures in the Dermis, contd. v. muscles – tighten skin & raise hairs (to get warmer) vi. fat – we all have a layer of fat (called the subcutaneous layer) underneath our dermis that insulates the body. vii. nerves – send signals to the brain, letting it know what you’re touching or is touching you. You can sense pain, pressure, hot, and cold. (I’ll have to draw nerves in the diagram)

11. #8 Structures, contd. Whew! Your skin is JAM-PACKED with all sorts of stuff. You look at it from the outside, and it looks so plain and simple. That’s on purpose. The outside has to deal with all sorts of harsh conditions, so it’s all dead skin cells, ready to flake off. …and you know the result of all that flaking, right? gross.

12. Yeah, doesn’t hurt #9 Structures, contd. Your hair and nails cover your body, too. Your nails are made of a special skin-like protein called keratin, which happens to be what your hair is made of, too. Your hair and nails are made of special cells that are thick and hardened. Why can you cut, chew, and chop them off? They are dead tissues with no working nerves to signal pain.

13. #10 DISORDERS of the Integumentary System When we… WAIT! Skin Disorders!?!? This could get nasty! I don’t… Uh, sorry, Joe. This isn’t a democracy. You lose. But we CAN spare you from some of the more rare and gross skin disorders that affect a few unlucky people. For now, get ready to hit the beach!

14. #11 Disorders, contd. Joe likes the beach. Who doesn’t???

15. #12 Disorders, contd. All that playing gets tiring, so Joe lays out on a towel for a while. …and he lays in the sun… …and bakes in the sun… …and roasts in the sun… …and he finally gets up to go home. He can tell he is BURNED to a near-crisp.

16. #13 Disorders, contd. The next morning, it’s obvious to Joe what he’s done. His friends joke with him the whole day—making fun, slapping his sore back, repeating “should’ve put on your sunscreen” a billion times… …and after a week of soreness and peeling, Joe will be fine again. But Joe better not fall into a pattern of burn/heal/burn/heal over his lifetime. All that sunlight can really fill him with regrets later on.

17. #14 Disorders, contd. Your skin knows more than a lot of people’s brains—that sunlight is RADIATION, and too much of it can be very damaging. In the presence of the stimulus of sunlight, your skin responds by making extra melanin – the pigment that gives your skin its color. This helps bounce sunlight off your skin to prevent it from absorbing too much radiation. This is how & why you tan. But if you overwhelm your skin’s ability to SLOWLY make melanin, it will absorb a lot of energy, burn (temporary pain), but most importantly, could set you up for possible future problems.

18. #15 Disorders, contd. Too many times of allowing your skin to be damaged by the Sun can lead to a condition called melanoma. Melanoma is a dangerous skin cancer that could be fatal if allowed to spread to other organs. Protect yourself! Wear sunblock. Don’t obsess over your tan. Watch your freckles & moles for any danger signs. Protect yourself! I promise!

19. #16 Disorders, contd. What do these people have in common? If you said that their hair follicles have fallen out, then you’re right! Forms of Male Pattern Baldness are known to affect some women too!

20. #17 Disorders, contd. Boy, the teenage years can be rough on the skin. Puberty hits and pimple breakouts flare up. You experiment with creams and medicated pads that you get at the store, but what really works? Everyone’s different, so it’s really hard to say, but if nothing seems to work, you might consider a visit to the dermatologist. Acne is really just bacteria- infected hair follicles. The bacteria love skin oil, and when a sebaceous gland clogs up, they’ll go crazy. If it’s absolutely driving you crazy, then go see the doc!

21. What would happen if your Integumentary System stopped working? Let’s review the functions to see. #18 Review • Protection from environment & germs • Joe would fry his organs in sunlight & germs & critters • would devour his body. • Regulates body temperature • Joe would have a VERY hard time cooling off while • exercising…he could actually overheat & hurt his brain. • Excretes (gets rid of) wastes in sweat • This wouldn’t be a huge deal…you have other ways of • getting rid of these wastes. • Has nerves to sense the environment • Joe would have no clue if he stood against a hot stove or sat on a • cactus. He’d be CONSTANTLY injuring his body. • Produces vitamin D using sunlight • Joe would need to get his vitamin D from milk or foods so that his • bones stayed strong.

22. #19 Review How does the Integumentary System help maintain homeostasis? • When you’re hot, you sweat • When you’re cold, you get goosebumps • When you’re in sunlight, you protect yourself by tanning Stimulus : Response Bug crawling on you : nerves send signals, making you aware It’s hot : sweating It’s cold : goosebumps Standing in sunlight : tanning

23. #20 And That’s… The End !