Begin

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Begin
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The Muscular System
POWER
Yeahjust like that!
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1 Review
Function job Structure a part/object Homeost
asis keeping balance in the body. Equilibrium
inside. Stimulus Response how the body
responds to changing conditions
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2 Muscular System Overview
What makes up the most weight in your body?
Bones? Fat? Skin? Fingernails? Something else?
Of course, its muscle!
The same goes for a cow. All those cuts of beef
that we like are just the cows muscles
surrounded by fat. Yep!
Your muscles do more than just move you around,
though. Lets see.
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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 internal organs, as
well as those attached to bones.
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4 FUNCTIONS of the Muscular System
How do muscles cause movement? Well, muscles are
masters of pulling on bones. They cant push at
alltheyre 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.)
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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 around and give it a shot because
you wanted to.
Now, stop your heart from beating. If you cant,
make your stomach quit squishing up your most
recent meal.
Some muscles are controllable by your thinking,
others arent!
A voluntary muscle can be controlled by thinking.
For example, the biceps of your upper arm.
Involuntary muscles automatically contract on
their own, such as your stomach.
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6 STRUCTURESTypes of Muscle
Muscles arent all built the same way, because
they have different jobs to perform. The
STRONGEST muscles you have are the ones that
youd use to shove a refrigerator around or swing
a golf club hard with. Theyre strong, but tire
pretty quickly. ? These are called
1. skeletal muscles
Two things about skeletal muscles a.) theyre
all voluntary and b). they are attached to bones
structures needing movement
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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)
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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 at changing
the shape and thickness of organs like your
intestines, your bladder, and your blood vessels.
2. smooth muscles

• theyre involuntary, working
• automatically
• b. found in internal organs
• (intestines, blood vessels)

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9 Structures/Types of Muscle, contd.
Not EVERY one of your internal organs uses smooth
muscle to run, though. Weve already talked
about your heart and its never-resting job. The
heart is made of cardiac muscle, which never has
to rest to keep going for as long as you live.
3. cardiac muscle
a. involuntary, thankfully b. found only in the
heart
so, those are the three types of muscle, what
they do, and where theyre found!
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10 DISORDERS of the Muscular System
Lets not play around. Come here, Joe.
Please, please, please no osteoporosis!
No worries, Joe. Osteoporosis was a skeletal
system disorder. Youre safe.
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11 Disorders, contd.
There are many reasons why someone would be
confined to a wheelchair. Brain or nerve damage
(paralysis) could be one, but another genetic
birth defect that affects thousands around the
country is muscular dystrophy.
Muscular dystrophy is a disease where a persons
muscles weaken after birth and the sick have
little control over them. Over time, people with
M.D. will often end up in wheelchairs as their
muscles fail them. Their minds are completely
healthy, though. No cure currently exists for
this disease. The MDA (Jerrys Kids) is the
most prominent charity searching for a cure.
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12 Disorders, contd.
The drive to be bigger, better looking, or an
improved athlete has caused people to pursue any
means possible to achieve these goals.
sigh Looks like Joes got quite a goal set for
himself.
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13 Disorders, contd.
Joe gets to work
and finds that instantaneous results arent
exactly happening.
Like so many people, Joe gets frustrated, wants
the easy way to success, and looks for a
short cut.
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14 Disorders, contd.
Joe meets up with a shady character known to
provide illegal drugs at the local gym. Which
drug is Joe after? Anabolic steroids.
Dang, Joe, what are you doing? Youre
breaking the law, spending a lot of money, and
youre about to wreck your body when some
hard work persistence wouldve gotten you where
you wanted.
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15 Disorders, contd.
The steroids work. Thats why so many people
risk so muchjailtime, humiliation, losing
friends, families, careers, and even permanent
health problems and DEATH. Joe is so
single-minded, though, that those risks dont
matter to him. Hes just glad they work.
Weve got to keep this powerpoint rated PG,
so were going to have to skip the health
problems that are about to affect Joe.
Sorry. However, please realize that abusing
anabolic steroids doesnt just cause embarrassing
side effects. Joe is now at risk for several
LIFE- THREATENING conditions that could
easily KILL him. Youll read more about another
day.
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16 Disorders, contd.
Joe made a bad, horrible choice. If he was doing
the steroids to make him better at sports, hed
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
effects due to way too many hormones. The
effects can be embarrassing to deadly. Here are
just a few
Men shrunken genitals, stunted growth,
cancer Women shrunken breasts, body hair, cancer
This should be an easy decision for
everyone. Anything illegal that has to be
injected to work is illegal for a reason. Stay
off the roids.
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17 Review
Gotta Have This System!
Why is the muscular system important? What if
Joes disappeared?
Function 1 allows for movement
Joe would collapse to the ground and never be
able to eat, drink, or fight off any attacker.
Hed die of thirst, starvation, or being eaten
by fire ants.
Function 2 used in internal organs for life
functions
Joe would instantly empty his bladder, hed, uh,
poop his pants, hed stop digesting his food,
hed stop moving air in out of his body, and
his blood would come to a standstill. Give
him about 5 minutes, max.
Help!?!
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18 Review, contd.
Homeostasis? The muscles in your body keep your
bloodflow and breathing going at whatever rate
your body needs at the moment. Also, they allow
you to digest food, eliminate certain wastes, and
can even warm your body up.
Stimulus Response How about You are feeling
really cold your body shivers, trying to warm
you up
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19 And Thats
Da End!