Begin

The Muscular System

Yeah…just like that!

#1 ReviewFunction = job

Structure = a part/object

Homeostasis = keeping balance in the body. Equilibrium inside.

Stimulus : Response = how the body responds to changing conditions

#2 Muscular System OverviewWhat makes up the most weight in your body? Bones? Fat? Skin?

Fingernails? Something else?

Of course, it’s muscle!The same goes fora cow. All those cutsof beef that we likeare just the cow’s muscles surroundedby fat. Yep!

Your muscles do morethan just move youaround, though. Let’ssee.

#3 Muscular Sys. Overview

You have over 600 muscles responsible for moving body parts,but many more muscles work internally to keep you going.The muscular system consists of all the muscles in your internalorgans, as well as those attached to bones.

#4 FUNCTIONS of the Muscular System

How do muscles cause movement? Well, muscles are masters ofpulling on bones. They can’t push at all—they’re not built that way.But they can pull, pull, pull.

1. moves body parts by contracting (getting shorter)

2. controls life functions (breathing, heartbeat, digestion,etc.)

#5 Muscle Control

Can you rub your tummy while you pat your head? Try it.

Whether or not you succeeded, you at least were able to move aroundand give it a shot because you wanted to.

Now, stop your heart from beating. If you can’t, make your stomachquit squishing up your most recent meal.

Some muscles are controllable by your thinking, other’s aren’t!

A voluntary muscle can be controlled by thinking. For example,the biceps of your upper arm.

Involuntary muscles automatically contract on their own, such asyour stomach.

#6 STRUCTURES—Types of Muscle

Muscles aren’t all built the same way, because they have differentjobs to perform. The STRONGEST muscles you have are the onesthat you’d use to shove a refrigerator around or swing a golf clubhard with. They’re strong, but tire pretty quickly. These are called:

1. skeletal muscles

Two things about skeletal muscles: a.) they’re all voluntary andb). they are attached to bones & structures needing movement

#7 Structures/Types of Muscle, contd.Skeletal muscles that move your body around come in two varieties:

flexors and extensors. Flexors and extensors usually work in pairs,as seen here:

i. flexor – bends a joint (biceps)

ii. extensor – straightens a joint (triceps)

biceps bendsthe arm

tricepsstraightens it

#8 Structures/Types of Muscle, contd.

Another type of muscle, called smooth muscle, is found lining the internal organs. Acting like rings of rubber bands, they are good atchanging the shape and thickness of organs like your intestines, yourbladder, and your blood vessels.

2. smooth muscles

a. they’re involuntary, working automatically

b. found in internal organs (intestines, blood vessels)

Layers of smooth muscle makethe stomach able to grind food

#9 Structures/Types of Muscle, contd.

Not EVERY one of your internal organs uses smooth muscle to run,though. We’ve already talked about your heart and its never-restingjob. The heart is made of cardiac muscle, which never has to rest tokeep going for as long as you live.

3. cardiac muscle

a. involuntary, thankfullyb. found only in the heart

so, those are the three typesof muscle, what they do, andwhere they’re found!

#10 DISORDERS of the Muscular System

Let’s not play around. Come here, Joe.

Please, please, please no

osteoporosis!

No worries, Joe.Osteoporosis was askeletal systemdisorder. You’resafe.

#11 Disorders, contd.

There are many reasons why someone would be confined to a wheelchair. Brain or nerve damage (paralysis) could be one, butanother genetic birth defect that affects thousands around the countryis muscular dystrophy.

Muscular dystrophy is a disease where a person’s muscles weakenafter birth and the sick have little control over them. Over time,people with M.D. will often end up in wheelchairs as their musclesfail them. Their minds are completely healthy, though. No curecurrently exists for this disease. The MDA (Jerry’s Kids) is the most prominent charity searching for a cure.

#12 Disorders, contd.The drive to be bigger, “better” looking, or an improved athlete hascaused people to pursue any means possible to achieve these goals.

*sigh* Looks like Joe’s got quite a goal set for himself.

#13 Disorders, contd.Joe gets to work…

…and finds that instantaneous results aren’t exactly happening.

Like so many people, Joe getsfrustrated, wants the easy wayto success, and looks for a shortcut.

#14 Disorders, contd.

Joe meets up with a shady character known to provide illegal drugsat the local gym. Which drug is Joe after?Anabolic steroids. Dang, Joe, what

are you doing?You’re breakingthe law, spendinga lot of money,and you’re aboutto wreck your bodywhen some hardwork & persistencewould’ve gotten youwhere you wanted.

#15 Disorders, contd.The steroids work. That’s why so many people risk so much—jailtime,humiliation, losing friends, families, careers, and even permanent health problems and DEATH. Joe is so single-minded, though, thatthose risks don’t matter to him. He’s just glad they work.

We’ve got to keep this powerpoint rated PG, sowe’re going to have to skip the health problemsthat are about to affect Joe. Sorry.However, please realize that abusing anabolicsteroids doesn’t just cause embarrassing side effects.Joe is now at risk for several LIFE-THREATENING conditions that could easilyKILL him. You’ll read more about another day.

#16 Disorders, contd.

Joe made a bad, horrible choice. If he was doing the steroids to make him better at sports, he’d be nothing but a cheater. In this case, all he cheated was his health, which is never, ever worth it.

Steroid abuse can lead to dozens of side effectsdue to way too many hormones. The effects canbe embarrassing to deadly. Here are just a few:

Men: shrunken genitals, stunted growth, cancerWomen: shrunken breasts, body hair, cancer

This should be an easy decision for everyone.Anything illegal that has to be injected to workis illegal for a reason. Stay off the roids.

#17 ReviewWhy is the muscular system important? What if Joe’s disappeared?

Function 1: allows for movementJoe would collapse to the ground and never be able to eat, drink, orfight off any attacker. He’d die of thirst, starvation, or being eaten byfire ants.

Help!?!

Function 2: used in internal organs for life functions

Joe would instantly empty his bladder, he’d, uh, poop his pants, he’dstop digesting his food, he’d stopmoving air in & out of his body,and his blood would cometo a standstill. Give himabout 5 minutes, max.

#18 Review, contd.Homeostasis?The muscles in your body keep your bloodflow and breathing going atwhatever rate your body needs at the moment. Also, they allow you todigest food, eliminate certain wastes, and can even warm your body up.Stimulus : ResponseHow about…

You are feeling really cold : your body shivers, trying to warm you up

#19 And That’s…