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The Muscular System
Chapter 6.1
Did you know that ?
- more than 50% of body weight
is muscle !
- muscle is made up of proteins
and water
Fun Facts Question 1:
How many muscles does it take to smile?
A: 17
B: 21
C: 32
D: 49
Fun Facts Question 2:
How many muscles does it take to frown?
A: 13
B: 21
C: 29
D: 42
Fun Facts Question 3:
Where is the hardest working muscle located?
A: stomach
B: eye
C: heart
D: leg
Fun Facts Question 4:
Where is the largest muscle in the body
located?
A: abdominal region
B: arm
C: buttock
D: leg
Info About Muscles
• Only tissue able to contract
• create movement by flexing and extending
joints
• Contain many mitochondria to create
energy (ATP) from sugar during Cellular
respiration
– When a muscle is fatigued (tired) it is unable
to contract because of a lack of oxygen
The Muscular System
• responsible for all movement
• three basic types of muscle
– Skeletal
– Cardiac
– Smooth
Skeletal Muscle
•
•
•
•
attached by tendons to bones
Voluntary- subject to conscious control
Found in the limbs
Produce movement, maintain posture,
generate heat, stabilize joints
Smooth Muscle
• Involuntary- no
conscious control
• Found mainly in the
walls of hollow organs
– Peristalsis: alternate
contractions that push
food through digestive
tract
Cardiac Muscle
• Involuntary, rhythmic
contractions
• Found only in the heart
• Heart muscle cells behave
as one unit
• Heart always contracts to
its fullest extent = heart
beat
How are Muscles Attached to
Bone?
• always attached to at least 2 points
– Origin- attachment to an immovable or less movable
bone
– Insertion-attachment to a movable bone
• When muscles contract, insertion moves towards origin
Insertion
Origin