Term
| What initiates muscle contraction? |
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Definition
| CA induced Ca released (EC Ca entry triggers Ca release from SR) to initiate contraction |
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Term
| When does relaxation occur? |
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Definition
| When Ca is actively pumped out of the cell and back into the SR via the Ca ATPase |
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Term
| What is inotropism? It is correlated directly with what? |
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Definition
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Term
| ___________ NS activity has a positive inotropic effect on myocardium. |
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Definition
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Term
| What receptor is activated in the sympathetic NS that has inotropic effects and what does this cause? |
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Definition
| B1 receptor - Gas activation and increased cAMP |
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Term
| What 2 proteins are phosphorylated to produce the increase in contractibility by increasing IC Ca concentration? |
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Definition
| 1) Sarcolemnal Ca channels 2) Phospholamban |
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Term
| What occurs when sarcolemnal Ca channels are phosphorylated? |
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Definition
| Increases inward Ca current triggering more Ca release from SR |
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Term
| What occurs when phospholamban is phosphorylated? |
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Definition
| Stim. Ca ATPase in the SR increasing rate of relaxation (more time for ventricular filling) and more Ca to be stored for the next beat |
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Term
| Parasympathetic NS activity has a ________ ionotropic effect on the atria. |
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Definition
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Term
| The activation of what receptor in the parasympathetic NS causes decreased contractility? |
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Definition
| M2 receptor - Gak activation and inhibition of AC (decreased cAMP) |
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