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1. Origin Attachment of a muscle's tendon to the stationary bone. Immovable.
2. Insertion Attachment of the muscle's other tendon to the moveable bone. Moves when
muscle contracts.
3. Lever A rigid structure that can move around a fixed point called fulcrum. Is acted on
at two different points by two different forces. (load and effort) ELF: Effort, Load,
Fulcrum
4. fulcrum fixed point on a lever
5. Effort Causes movement
6. Load Resistance, which opposes movement
7. Mechanical ad- When the load; resistance, is closer to the fulcrum than the effort; power that
vantage causes movement
8. Mechanical dis- If the load is farther from the fulcrum and the effort is applied closer to the fulcrum,
advantage then a relatively large effort is required to move a small load.
9. First Class Lever Fulcrum in middle, between the effort and the load. Can have either mechanical
advantage or disadvantage. example: scissors, head movements; EFL
10. Second Class Load in middle, between the fulcrum and the effort. Always mechanical advantage.
Lever Example: plantar flexion, wheel barrow, ELF
, BIOS252 Midterm
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11. Third Class Lever Effort in middle, between fulcrum and the load. Mechanical disadvantage. Most
skeletal muscle contractions are third-class levers. Example: Biceps brachii contrac-
tion when bicep curling, tweezers. FEL
12. Fascicles skeletal muscle fibers (cells) within a muscle are arranged in bundles. May form
one of five patterns with respect to tendons.
13. Parallel Fascicle parallel to longitudinal axis of muscle; terminate at either end in flat
tendons. Example: Sternohyoid muscle
14. Fusiform Fascicle parallel to longitudinal axis of muscles; terminate in flat tendons; muscle
tapers toward tendons, where diameter is less than at belly. Example: Digastric
muscle
15. Circular Fascicle in concentric circular arrangements form sphincter muscles that enclose
an orifice (opening). Example: Orbicularis oculi muscle