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10 Cards in this Set
- Front
- Back
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Excitation - Contraction Coupling |
- Motor neuron conducts action potentials - Action potential travels from the brain --> transferred to muscle fibre by structures called transverse tubles - the T-tubules make contact with the sarcoplasmic reticulum (SR) - excitation contraction coupling --> convert action potential to contraction --> calcium ions are responsible |
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Cross Bridge Cycle |
- contraction of muscle has enough force to move the skeleton - contraction occurs from many molecular events --> cross bridge cycle - Cross Bridge: attachement of myosin with actin within the muscle - Cross bridge cycling: repeated attachement of myosin and actin Steps 1. Cross Bridge Formation: activated myosin head binds to actin, forming a cross bridge 2. Power stroke: ADP released and activated myosin head pivots 3. Cross Bridge Detachement: ATP binds to Myosin head making the bond between the head and actin weaker --> myosin head detaches 4. Reactivation of Myosin Head: ATP hydrolised to ADP and Inorganic Phosphate |
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Sarcromere |
- Functional unit of contraction for striated muscle |
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How are muscles stimulated? |
- by motor neurons - each neuron may innervate many muscle fibers --> not all fibers are excited at the same time - total force contraction depends on how many fibers are stimulated |
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Motor Unit |
set of muscle fibers stimulated by single nerve fiber |
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Size of a Motor Unit |
number of muscle fibers stimulated by a single motor nerve fiber |
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Precision of Muscle Response |
governed by the size of the motor unit - small muscles that react rapidly and with precision have small motor units - large muscles that do not require a good degree of precision, have many muscle fibers in each motor unit |
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Action Potential |
electrochemical signal generated by motor neurons |
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Isotonic Contraction |
Constant Tention - constant displacement - latent period is small |
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Isometric Contraction |
Constant Length - longer latent period - higher load, longer latent period |
