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Integumentary System

the WHAT?

That stuff! Your SKIN!

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

#1 Integumentary System Overview

But it IS an organ, and one ofyour largest! Take your skin off, and you’d weigh 5 to 10 pounds less, but more importantly, you wouldn’t last very long.

(your skin grows as you do…and ifyou become dramatically smaller,you’ll be left with your full-sizedorgan)!

Do you ever think of your skin as an organ? Probablynot very often, if ever.

#2 Integ. Sys. Overview, contd.Your skin has a BRUTAL job. It’s your only major organon the OUTSIDE of your body, so it has to deal withconditions that would totally overwhelm your heart orkidneys or any other organ. Because of this constantattack, your skin cells die & are replaced every month!

Your integumentary system is any surface covering forthe body. We’ll focus on the major ones (skin, hair, nails).

Technically, your integumentary system also deals withthe tissues that line the inside of your organs—like thelining 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…

#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

(vitamin D is vital in helpingyour bones absorb calcium)

#4 Functions, contd.

Those are some very important functions, eh?

Now, let’s see the structures that make all these functionshappen. There’s a lot—be warned!

#5 STRUCTURES of the Integumentary System

Your skin is the largest organ of the body. It has a lot ofimportant jobs, which we just saw, and is made of two mainlayers:

fattylayer

a. epidermis – this is the thin outer layer of constantly replaced dead cells.The epidermis isthe body’s barrierto the outside world.

b. dermis – this is thethicker inner layercontaining thefollowing structures:

#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 upout of the surface of the skin

iv. blood vessels including smallarteries, veins & capillaries

(are you writing these structures in the blanks on the back of your page?)

#7 Structures in the Dermis, contd.

v. muscles – tighten skin & raisehairs (to get warmer)

vi. fat – we all have a layer offat (called the subcutaneouslayer) underneath our dermisthat insulates the body.

vii. nerves – send signals to thebrain, letting it know whatyou’re touching or is touchingyou. You can sense pain,pressure, hot, and cold.

(I’ll have to draw nerves in the diagram)

#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 andsimple. That’s on purpose. The outside has to deal withall 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?

#9 Structures, contd.Your hair and nails cover your body, too. Your nails are made of a special skin-like protein called keratin, whichhappens to be what your hair is made of, too.

Your hair and nails are made of special cells that are thickand hardened. Why can you cut, chew, and chop them off?They are dead tissues with no working nerves to signal pain.

Yeah, doesn’t hurt

#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 fromsome of the more rare and gross skin disorders that affecta few unlucky people. For now, get ready to hit the beach!

#11 Disorders, contd.

Joe likes the beach. Who doesn’t???

#12 Disorders, contd.All that playing gets tiring, so Joe lays out on a towel fora 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.

#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, slappinghis sore back, repeating “should’veput on your sunscreen” a billiontimes…

…and after a week of sorenessand peeling, Joe will be fine again.

But Joe better not fall into apattern of burn/heal/burn/healover his lifetime. All that sunlightcan really fill him with regrets later on.

#14 Disorders, contd.Your skin knows more than a lot of people’s brains—thatsunlight is RADIATION, and too much of it can be verydamaging.

In the presence of the stimulus of sunlight, your skin respondsby making extra melanin – the pigment that gives your skin itscolor. This helps bounce sunlight off your skin to prevent itfrom absorbing too much radiation. This is how & why you tan.

But if you overwhelm your skin’s abilityto SLOWLY make melanin, it will absorba lot of energy, burn (temporary pain),but most importantly, could set you upfor possible future problems.

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

Ipromise!

#16 Disorders, contd.What do these people have in common?

If you said that their hair follicleshave fallen out,then you’re right!

Forms of MalePattern Baldnessare known toaffect some womentoo!

#17 Disorders, contd.Boy, the teenage years can be rough on the skin. Pubertyhits and pimple breakouts flare up. You experiment withcreams and medicated pads that you get at the store, butwhat really works? Everyone’s different, so it’s really hardto say, but if nothing seems to work, you might consider avisit to the dermatologist.

Acne is really just bacteria-infected hair follicles.The bacteria love skin oil,and when a sebaceous glandclogs up, they’ll go crazy.

If it’s absolutely driving youcrazy, then go see the doc!

#18 ReviewWhat would happen if yourIntegumentary System stoppedworking? Let’s review thefunctions to see.

1. Protection from environment & germsJoe would fry his organs in sunlight & germs & critterswould devour his body.

2. Regulates body temperatureJoe would have a VERY hard time cooling off while exercising…he could actually overheat & hurt his brain.

3. Excretes (gets rid of) wastes in sweatThis wouldn’t be a huge deal…you have other ways of getting rid of these wastes.

4. Has nerves to sense the environmentJoe would have no clue if he stood against a hot stove or sat on a cactus. He’d be CONSTANTLY injuring his body.

5. Produces vitamin D using sunlightJoe would need to get his vitamin D from milk or foods so that hisbones stayed strong.

#19 ReviewHow 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 awareIt’s hot : sweatingIt’s cold : goosebumpsStanding in sunlight : tanning

#20 And That’s…