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What happens when ATP is depleted?5. A twitch lasts 10-100ms, where as a skeletal muscle AP only lasts 1-2ms allowing The AP has already gone up & down before any force of twitch has been generatedWhy is there a delay in force generation after the action potential in a skeletal muscle?How are prolonged (several seconds), stable tensions produced from nerves & muscles that use inherently all or none AP that last only a few ms?Why is a tetanus contraction generate 3-4 times the force of a twitch?6. 2 signaling mechanisms that control tension produced from a muscle
A single motor neuron can control multiple muscle fibers (cells)How is this controlled by the CNS?7. Specializations of cardiac muscleIntercalated discs- mechanically connect adjacent cellsGap junctions- allow action potentials to move between adjacent cellsPacemaker cells- endogenously generate action potentialsoAllow heart to beat on its own oCycles of depolarizations about once per secondAction potentials last 100-500 ms, thus preventing tetanus 8. In the right atria, there is a population of muscle cells that have a special grouping of channels that allow it to have pacemaker activity = SA NodeFunny sodium channels are open; & closing K channelsoFunny because they start to depolarize near resting membrane potential (-60 mV)o