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10 Cards in this Set
- Front
- Back
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Explain the process of excitation-contraction coupling in a step-by-step sequence (the right sequence, we should mention J).
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1. Release of Ca into sarcoplasm.
2. Binding of Ca to troponin C 3. Troponin C confirmational change 4. Tropomyosin pulled from active site 5. Myosin ADP leaves 6. Power stroke 7. ATP binds to myosin 8. Repeated until no more action potential |
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Hypothesize the effects of disruption in excitation-contraction coupling on the ensuring muscle contraction. For example, what would be the effect of a drug that causes opening of the ryanodine receptors in skeletal muscle?
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If drug opens ryanodine receptors then Ca would go into sarcoplasm and cause contractions without action potential
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Compare and contrast the source of ATP at rest with energy sources during light and strenuous activity. Remember to include the role of creatinine phosphate
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Phosphocreatine is most immediate source of ATP for muscles
1. at rest- ATP donates PO4 to Cr 2. exercise- CrP donate PO4 for ADP at myosin head Other sources of ATP: 1. FFA- free fatty acids at rest and low exercise levels 2. Carbs- greater levels of exercise, (glycogen in muscles- glucose in blood) |
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Describe rigor mortis...
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When person dies Ca is able to flood the sarcoplasm and body stops creating more ATP therefore muscles stay in contracted position... until proteins naturally degrade
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Compare and contrast isometric with isotonic contractions.
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Isometric- same length as cross bring changes tension (increase in tension/force)
Isotonic- same tension as cross bring shortens muscle length (no change in tension/force) |
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Define the series elastic element and describe its influence on skeletal muscle contraction.
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Tendons and elastic tissue in muscle that stretch... the length tension curve describes the how the length of muscles affect tension
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Describe the length of sarcomere and tension...
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a. tension depends on length
b. maximum tension occurs at 2.0-2.2mcm (Lo) c. sarcomere < 2.0 mcm actin overlaps, less normal interaction and tension decreases d. more interactions = greater tension |
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Describe the following terms as pertaining to whole muscle...
a. active tension b. passive tension c. total tension |
a. active = what the cross bridges do
b. passive= stretching membranes (rubberband) c. sum of active and passive |
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Compare and contrast preload and afterload (the two types of loads)
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Pre- muscle "feeling" load prior to beginning of contraction -
ex. Briefcase hanging on hand After- muscle doesnt "feel" load until contraction begins ex. books on table |
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Explain the muscle details of preloading...pertaining to the effects on
a. myosin/actin overlap b. bridge interaction c. force (tension) |
a. myosin/actin overlap- less
b. less c. less |
