10 the muscular system interactions of skeletal muscles
TRANSCRIPT
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10The Muscular System
Interactions of Skeletal Muscles
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Muscle tissue includes all contractile tissue skeletal muscles take center stage!
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Interactions of Skeletal Muscles in the Body
The arrangement of muscles permits them to work together or in opposition to achieve a variety of movements.
Muscles can only pull then can never push!!!
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Interactions of Skeletal Muscles in the Body
Origin – muscle attached to the immovable (or less) movable bone.
Insertion – muscle attached to the movable bone.
Ex. Spring on a screen door.
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Interactions of Skeletal Muscles in the Body
As a muscle shortens:
The insertion moves towards its origin.
Whatever one muscle or group of muscles does another muscle or group of muscles must “undo” the action
Flex the elbow extend the elbow
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Interactions of Skeletal Muscles in the Body
Skeletal muscles work together or in opposition
A muscle cannot reverse the movement it produces
Another muscle must undo the action
Muscles with opposite actions lie on opposite sides of a joint
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Interactions of Skeletal Muscles in the Body
Prime mover
Agonist
Provides major force for a certain movement
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Interactions of Skeletal Muscles in the Body
Antagonist
Muscles that oppose, or reverse, a particular movement.
Can also help to regulate the action of the prime mover by contracting to provide some resistance
When prime mover is active relaxed and stretched
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Interactions of Skeletal Muscles in the Body
Prime movers and antagonists lie on opposite sides of the bone!
Depending on the movement:
A prime mover can become an antagonist
An antagonist can become a prime mover
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Interactions of Skeletal Muscles in the Body
Help prime mover:
Add extra force to same movement
Reduce undesirable or unnecessary movements that might occurs at prime mover contracts.
Synergist
Syn = together; erg = work
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Interactions of Skeletal Muscles in the Body
Synergist
Example – if a muscle crosses two or more joints movement occurs at all the joints stabilize so movement doesn’t occur.
Example – Muscles that cause finger flexion found in forearm
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Interactions of Skeletal Muscles in the Body
Example – scapula
Held to the axial skeleton only by muscles, but is also freely movable.
Fixators immobilize the scapula so that only the desired movements occur at the shoulder joint.
Fixator
A synergist that immobilizes a bone or a muscle’s origin
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Interactions of Skeletal Muscles in the Body
Prime movers, antagonists, and synergists work together to produce smooth coordinated, and precise movements
A muscle can switch roles depending on the movement!