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12 Cards in this Set
- Front
- Back
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By how much is the sarcomere shortened in each power-stroke?
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10 nm
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Define work.
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It is the product of force by distance
W= L x D. SI unit is joule |
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Define tension.
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Tension (in physics): another word for force, implying stretching (cf. compression)the act of being stretched or tense, or pulling force. Thus muscle tension=pulling force in the muscle
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What are the Two sources of ‘tension’ in the contracting muscle:
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1-Tension developed when the muscle is stimulated to contract isometrically (the total tension)
2-the passive tension exerted by the unstimulated muscle |
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Define active tension.
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The difference between the two values at any length is the amount of tension actually generated by the contractile process, the active tension
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Define resting length.
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the length of the muscle at which the active tension is maximal is usually called its. The term comes originally from experiments demonstrating that the length of many of the muscles in the body at rest is the length at which they develop maximal tension.
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What determines the velocity of muscle contraction.
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The load on the muscle (inverse relationship)
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Define force.
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That which changes a body's state of rest or motion.
SI unit is newton. |
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Define summation.
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ii. The fact that intra-myocyte Ca++ levels remain elevated for 50 ms after a stimulus, and the tension does not remain to normal till another 30 ms a 2nd stimulus applied within 8 ms to 80 ms from the 1st stimulus will have an additive effect, known as summation.
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Define 'treppe' effect.
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A phenomenon in cardiac muscle first observed by H.P. Bowditch; if a number of stimuli of the same intensity are sent into the muscle after a quiescent period, the first few contractions of the series show a successive increase in amplitude (strength). Syn: staircase phenomenon.
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Define the stretch reflex.
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When a skeletal muscle with an intact nerve supply is stretched, it contracts. This response is called the stretch reflex
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Which neurotransmitter is involved in the monosynaptic stretch reflex?
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Glutamate
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