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32 Cards in this Set
- Front
- Back
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Tropomyosin |
Lies along actin in the groove formed by the double helix Inhibits Actin-Myosin interactions |
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Troponin |
Moves tropomyosin (uncovering active actin sites) when activated by Ca++ |
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T-tubular system |
Distributed around myofibrils so that each sacromere has 2 triads |
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Triad from T-tubular contains |
1. 2 vesicles (terminal cisternae) 2. 1 T tubule (transverse tubules) |
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Sliding filament model |
1. Contraction occurs as myosin and actin slide past each other 2. myosin cross bridges attach and detach from actin filaments 3. Energy for this movement is provided by ATP hydrolysis (breakdown) |
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Cross bridges |
1. Provide mechanical power strikes 2. Perform repeated, no synchronous strokes 3. Contain actin activated ATPase |
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How do myosin move actin |
1. Myosin heads attach and cock when active sit become available and ATP attaches to head 2. ATP is hydrolyzed causes myosin to straighten moving the actin with them (power stroke) |
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Excited contraction coupling |
The process of Ca being released when signaled by a electrical signal from nerve Caused myoactin crossbridge contraction |
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How do muscle relax |
1. Ca is always activity pumped into SR 2. So if a nerve does not signal the release of Ca then it will disapate and no longer signal troponin to move the tropomyosin |
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Type 1 muscle fibers |
Found in endurance athletes (slow twitch) Slower CA release and uptake by SR Low gycolytic capacity Large and numerous mitochondria |
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Muscle fibers are identified by 2 distinct characteristics |
1. Contractile 2. Metabolic |
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Fast twitch fibers |
Type 2 (speed/sprinters) 1.vHigh myosin ATPase activity 2. Rapid CA release and uptake 3. Causes high rate of crossbridge turnover 4. Generations high force 5. Relys on anaerobic metabolism |
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IIa and IIb fibers |
IIa fast shortening speed good for both anaerobic and aerobic energy IIb most rapid shortening velocity and relys on anaerobic energy |
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Motor unit |
One motor neuron and ALL the fibres it innervates |
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Action potential |
Initiated at axon hillock Propagates along motor nerve Facilitated by myelin sheath |
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What do AP cause |
Release of neurotransmitters at motor end plate/neuromuscular junction |
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Tendons origin and insertion |
Origin: more stable bone Insertion: moving bone Connect muscle to periosteum of bon |
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Chemical composition of muscle |
75% water 20% protein 5% salts, ions, macronutrients, phophate |
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Flow of blood through muscle is |
Rythmic |
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3 main fiber arrangements of muscle |
1. Fusiform (parallel) 2. Pennate (oblique angle) 3. Bio/multi pennate (multiple angles) |
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What does the fiber arrangement of a.muscle influence |
1. Force generating capacity 2. Physiologic cross section |
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What NT is released at muscles end plate |
Acetylcholine |
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Slow twitch muscle metabolic pathway |
CAC ETC Aerobic |
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Fast twitch IIa metabolic pathway |
Glycolysis Anaerobic lactic |
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Fast twitch IIb metabolic pathway |
Aka glycolytic fibers High energy phosphate compounds alactic anaerobic |
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How do you increase force of a muscle |
Increase frequency of AP |
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Depolarization of T-tubules causes |
1. Ca to be released 2. cross bridge formation continue if AP continues and therefore Ca continues to be released |
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Sodium potassium pump |
3 Na out 2 K in (Remember salt NaCl high outside of cell) |
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Lin cox |
Swimmer in cold water Swam English channel at 15 |
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In cold exercise depends on |
1. Maintaing warm body (increase blood to core) 2. preventing local cold injury e.g. frostbite (increase blood to extremities) |
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How to prepare for cold |
Gradually increase exposure Increase insulation |
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Cold induced vasodilation |
Increased blood flow to extremities to prevent frostbite |
