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36 Cards in this Set
- Front
- Back
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What are the 7 functions of muscle? |
energy conversion heat production shock absorption circulation cosmetic posture movement |
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Describe skeletal muscle |
striated multinucleated T-tubules troponin voluntary no junctions |
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What is excitability? |
ability to contract |
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What is contractibility? |
ability to shorten |
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What is extensibility? |
Ability to lengthen |
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What is elasticity? |
ability to return to original form |
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What are the layers of muscle? |
Epimysium: outer layer Perimysium: around bundles Endomysium: between fibers |
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What location is the most commonly injured site? |
musculo-tendinous junction |
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What is a motor unit? |
1MN and the specific fibers it innervates |
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What is a motor pool? |
collection of MNs that innervate a whole muscle |
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What factors limit healing? |
1. infection 2. transection 3. contusion/strain 4. myositis ossificans |
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What is the series elastic component in muscle? |
tendon |
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What is the order of fiber recruitment? |
Starts with Type I As intensity increase, Type IIa is then recruited At maximal intensity, Type IIb in then recruited |
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What is tetanus? |
if you increase frequency, you can produce more force and reach a higher speed |
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Describe the length-tension relationship |
optimal sarcomere length leads to most efficient contractions |
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Describe concentric contraction |
positive work muscle shortens |
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Describe eccentric contraction |
negative work muscle lengthens |
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Describe isometric contraction |
no work muscle length remains constant |
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Which contraction produces the most force? |
eccentric |
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Which type of contraction is used most commonly throughout the day? |
eccentric |
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What type of exercise has controlled velocities? |
isokinetic |
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Describe Fusiform fibers |
higher fiber length to muscle length ratio used for greater velocity |
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Describe pennate fibers |
used for greater force |
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As muscle continues to length: passive tension____ Stiffness_____ |
increase increase |
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What is another name for the increase in both passive tension and stiffness? |
Elastic recoil |
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What is hypertrophy? |
increase in size |
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What is hyperplasia? |
increase in # of muscle fibers |
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What conduction occurs when myelin wraps around a nerve and conduction passes through the nodes of ranvier? |
saltatory conduction |
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90% of muscle injuries are what? |
Muscle contusion OR Muscle strain |
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What stores calcium in muscles? |
sarcoplasmic reticulum |
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A "slight-moderate" stretch causes tension in muscles due to what? |
titin |
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"Extensive" stretching tension due to what? |
tendon/perimysium |
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How can you increase firing in a muscle contraction? |
# of motor units OR frequency |
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Regeneration of skeletal muscle requires intact what? |
basement membrane OR sarcolemma |
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When on bedrest, what fiber types do you lose? why? |
type 1 - they required too much energy to work properly |
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Which fiber type has a higher calcium reuptake/release? |
Type IIa/IIb |
