BIOS 252 Midterm Exam

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BIOS 252 Midterm Exam

• Origin

–Answer Attachment of a muscle's tendon to the stationary bone. Immovable.

• Insertion

–Answer Attachment of the muscle's other tendon to the moveable bone. Moves when muscle contracts.

• Lever

–Answer 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 –Answer Effort, Load, Fulcrum

• fulcrum

–Answer fixed point on a lever

• Effort

–Answer Causes movement

• Load

–Answer Resistance, which opposes movement

• Mechanical advantage

–Answer When the load; resistance, is closer to the fulcrum than the effort; power that causes movement

• Mechanical disadvantage

–Answer If the load is farther from the fulcrum and the effort is applied closer to the fulcrum, then a relatively large effort is required to move a small load. 1 / 2

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• First Class Lever

–Answer Fulcrum in middle, between the effort and the load. Can have either mechanical advantage or disadvantage. example –Answer scissors, head movements; EFL

• Second Class Lever

–Answer Load in middle, between the fulcrum and the effort. Always mechanical advantage. Example –Answer plantar flexion, wheel barrow, ELF

• Third Class Lever

–Answer Effort in middle, between fulcrum and the load. Mechanical disadvantage. Most skeletal muscle contractions are third-class levers. Example –Answer Biceps brachii contraction when bicep curling, tweezers. FEL

• Fascicles

–Answer skeletal muscle fibers (cells) within a muscle are arranged in bundles. May form one of five patterns with respect to tendons.

• Parallel

–Answer Fascicle parallel to longitudinal axis of muscle; terminate at either end in flat tendons. Example –Answer Sternohyoid muscle

• Fusiform

–Answer Fascicle parallel to longitudinal axis of muscles; terminate in flat ten- dons; muscle tapers toward tendons, where diameter is less than at belly. Example –Answer Digastric muscle

• Circular

–Answer

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