Chapter 11: The Muscular System Flashcards
Origin
The attachment of a muscles tendons to the stationary bone
Insertion
The attachment of a muscles tendon to the moveable bone.
Body
The fleshy portion of a muscle between the tendons.
Actions of a muscle
The main movements that occur when the muscle contracts.
Reverse muscle action
When the body of actions are reversed during specific movements. The origin and insertion of the muscle are switched.
Lever
A rigid structure that can be moved around a fulcrum.
Fulcrum
A fixed point in which the lever moves around.
Effort
The force which causes movement within a lever.
Load
The resistance which opposes movement within a lever.
Mechanical advantage
The load is closer to the fulcrum and the effort is further from the fulcrum.
Mechanical disadvantage
The load is further from the fulcrum and the effort is applied closer to the fulcrum.
3 categories of levers
First class
Second class
Third class.
First class lever
Fulcrum is between the effort and the load.
Produces mechanical advantage or disadvantage depending on which is closer to the fulcrum.
Second class levers
The load is between the fulcrum and the effort.
Mechanical advantage.
Sacrifices speed and ROM for power
Third class levers
Effort is between the fulcrum and the load.
Mechanical disadvantage.
Sacrifices power for speed and ROM.
Prime mover
Contracts to cause action of a muscle
Antagonist
Stretches and yields to the effects of a prime mover.
Parallel arrangement
Muscle fascicles are parallel to the longitudinal axis. Terminate at either end in flat tendons.
Fusiform arrangement
Fascicles nearly parallel to longitudinal axis. Terminate in flat tendons. Muscle tapers toward tendons.
Circular arrangement
Fascicles in concentric circular arrangements form sphincter muscles that enclose an orifice.
Triangular arrangement
Fascicles spread over broad area coverage at thick central tendon.
Pennate arrangement
Short fascicles in relation to total muscle length. Tendon extends nearly entire length of muscle.
Unipennate arrangement
Muscle fascicles arranged on only one side of tendon
Bipennate
Muscle fascicles arranged on both sides of centrally positioned tendons.
Multipennate arrangement
Fascicles attach obliquely from many directions to several tendons.
Synergist
Prevent unwanted movements at intermediate joints.
Aids prime mover.
