Transcript The Muscular System

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Section 13.3 page 526
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The human body has over 600 muscles!!!
A. Muscles move the bones of your
skeleton
B. Muscles keep your heart beating
C. Muscles perform required functions to
keep you alive. (Move your ribcage,
move food through your digestive
track, etc.)
A. Involuntary Muscle- not under
your conscious control.
1. Smooth Muscleinvoluntary and works automatically to
control many of your body functions
like:
* churning food in your stomach
* squeezing of food in your
esophagus and intestines (peristalsis)
* pulling the ribcage up and out for
breathing
Smooth muscles
react slowly and
tires slowly…
They also have no
STRIPES (striations)
2. Cardiac muscle- involuntary and
found in your heart.
Has stripes (striations) and does not
tire. It beats about 72
times per minute
for your lifetime.
B.Voluntary Muscle
1. Skeletal muscle
*attached to the bones of your
skeleton by tendons
*has striations
*conscious control voluntary
*reacts quickly,
but tires quickly.
Activity 1- Finger clicking…
1. Prediction: Will trial 1 or 2 have the
highest number of clicks. Why?
Trial 1:-_____
Trial 2:- _____
2. Outcome: Why did the results come out
the way they did? List 3 possible
reasons.
 a.
 b.
 c.
3. Prediction: What do you think will happen
with your other hand if you repeat the
same exercise? Faster/slower and why?
Trial 1: _____
4. Outcome:
III. Muscles at Work
1. Messages from the brain are
sent to your muscles
2. The muscle shortens or
contracts
3. The attached bone moves
A. Muscles
(page 529)
Work in Pairs
1. Since muscle cells can only
contract (then relax) they must
work in pairs…
2.When one muscle contracts,
the other must relax.
List three key points from each paragraph.
Paragraph 1:
1.
2.
3.
Paragraph 2:
4.
5.
6.
1.
2.
3.
4.
5.
With your arm at your side bend you
elbow upward at a 90 degree angle
Hold your palm facing up and open.
Balance a textbook in your open palm
for 3 minutes
Feel the biceps and triceps muscles.
Which of them feels hard?
1.
1.
2.
3.
Grasp the book in your hand
and hold your arm up over your head.
Bend it at the elbow so the book hangs
behind your back.
Slowly straighten your arm about twothirds of the way and hold the book in
that position for 3 minutes.
Which muscle feels hard and tense?
 1a.
Skeletal, smooth and cardiac
 1b. voluntary- under conscious
control, tire easily. (skeletal muscle)
involuntary- not able to
control, don’t tire easily (heart and
smooth muscle).
 1C. Person can’t move finger because
muscle not connected to the bone.
2a.Attached to the bones of the
skeleton ie. Upper arm and thigh.
2b.Bend the arm- biceps contracts
pulling the arm up and the triceps
relaxes.
Straighten the arm- triceps contracts
and the biceps relaxes.
2c.Exercising both muscles in a pair will
make them grow equally strong.