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24 Cards in this Set
- Front
- Back
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muscular system
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system which is comprised of the voluntarily controlled muscles of the body.
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Origin
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the attachment of a muscle's tendon to the stationary bone. Is usually proximal
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insertion
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the attachment of the muscle's other tendon to the movable bone. Is usually distal, and is usually pulled toward the origin
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Belly
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the fleshy portion of the muscle between the tendons
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lever
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a rigid structure that can move around a fixed point
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fulcrum
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the fixed point around which a level can move
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Effort (E)
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a force which acts on a lever, it causes movement, and is the force exerted by muscular contraction.
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Load or resistance
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a force which acts on a lever and opposes movement and is typically the weight of the body part that is moved.
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Mechanical Advantage
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Determined by the relative distance between the fulcrum and load and the point at which the effort is applied. This condition occurs when the load is closer to the fulcrum and the effort farther from the fulcrum, and only requires a relatively small effort to move a large load over a small distance.
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Mechanical Disadvantage
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Condition when the load is farther from the fulcrum and the effort is applied closer to the fulcrum, and a relatively large effort is required to move a small load.
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First-Class lever
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when the fulcrum is between the effort and the load. Can produce a mechanical advantage or disadvantage.
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Second class lever
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the load is between the fulcrum and the effort. They always produce a mechanical advantage because the load is always closer to the fulcrum than the effort.
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Third Class Lever
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The effort is between the fulcrum and the load. They operate like a pair of forceps and are the most common in the body. They always produce a mechanical disadvantage because the effort is always closer to the fulcrum than the load.
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Prime Mover
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within an opposing pair, the muscle which contracts to cause an action
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Antagonist
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within an opposing pair, the muscle which stretches and yields to the effects of the prime mover.
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Synergist
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Muscles which contract and stabilize the intermediate joints to prevent unwanted movements at intermediate joints or to otherwise aid the movement of the prime mover.
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fixator
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muscles which act to stabilize the origin of the prime mover so that the prime mover can act more efficiently by steadying the proximal end of a limb while movements occur at the distal end.
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Muscle naming by direction
*see table 11.2 on page 342-343 |
orientation of muscle fasicles relative to the body's midline
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Muscle naming by size
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relative size of the muscle
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muscle naming by shape
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relative shape of the muscle
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Muscle naming by action
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principal action of the muscle
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muscle naming by number of origins
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number of tendons of origin
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muscle naming by location
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structure near which a muscle is found
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muscle naming by origin and insertion
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sites where muscle originates and inserts
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