MNSR 6 - Skeletal Lever Systems Flashcards Preview

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Flashcards in MNSR 6 - Skeletal Lever Systems Deck (12)
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1
Q

Explain what happens to muscle with age.

A

As a person ages, there’s a gradual decrease in the number of muscle fibers, muscle converts to intramuscular fat, and muscle and bone lose their elasticity which hinders joint movement.

2
Q

What is maximum tension dependent on?

A

Maximum tension is dependent on 2 factors:

  1. cross-sectional area of muscle at its widest point
  2. Length of the muscle (max force is generated when the muscle is stimulated from its relaxed state)
3
Q

What are the two types of muscle?

A

There are two types of muscle:

  1. Fusiform muscle: fibers run parallel to the length of the muscle.
  2. Pennate muscle: fibers insert into a central tendon, are at an angle to the force-generating axis & generate more force than the fusiform muscles BUT smaller range of motion. There are three types:
    - unipennate: forearm
    - bipennate: thigh
    - multipennate: shoulder joint
4
Q

Differentiate between Agonist & Antagonist Muscles.

A
  1. Agonist/Primer mover/Normal: carry out the desired movement
  2. Antagonist muscles: assist agonist in controlled relaxation
5
Q

What can a lever do?

A

A lever can be used to magnify a force or change its direction.

6
Q

Define Mechanical Advantage.

A

MA = Fi/Fa
Fa < Fi = efficient –> mechanical advantage
Fa > Fi = inefficient –> mechanical disadvantage

7
Q

Discuss Class I Levers.

A

Fi fulcrum Fa
Fa < Fi OR Fa > Fi OR MA = 1 (EFFICIENT OR INEFFICIENT)
Head lift

8
Q

Discuss Class II Levers.

A

Fa Fi Fulcrum
Fa < Fi OR MA > 1 (EFFICIENT)
Calf Extension

9
Q

Discuss Class III Levers

A

Fi Fa Fulcrum
Fa > Fi OR MA < 1 (INEFFICIENT)
Bicep Curl

10
Q

Define Torque.

A

Torque is a force which causes rotational motion about a fixed point. Toure = Force x Perpendicular Distance

11
Q

Under what 2 conditions does equilibrium occur?

A
  1. Net force = zero

2. Net torque = zero

12
Q

State the formula for Equilibrium and Torque.

A

Sum of Clockwise torque = Sum of Anti-clockwise torque