Action Potential Generation in Skeletal Muscle

Action Potential Generation in Skeletal Muscle


action potential generation in skeletal muscle cells the sarcolemma is the plasma membrane of the skeletal muscle.
It separates the extracellular space from the
intracellular space Sodium ions are highly concentrated in the extracellular space outside of
the muscle cell whereas potassium ions are highly concentrated inside the cell
in the intracellular space this concentration of ions is what is seen at rest. Embedded in
the sarcolemma are voltage-gated sodium channels,
potassium, sodium, ATP-ase pumps and voltage-gated
potassium channels in order to initiate an action potential along the sarcolemma a stimulus from a neuron at the neuromuscular junction causes a wave of positive charge to
reach voltage-gated sodium channels on the sarcolemma the increase in positive charge causes
the voltage-gated sodium channels to open positively-charged sodium ion flood into
the cell following their concentration gradient This causes the inside of the membrane
near to the open sodium channel to become more positively
charged. This process is the depolarization of the sarcolemma. The
build-up a positive charge on the inside of the membrane eventually
causes the voltage-gated sodium channels to close at the same time voltage-gated potassium
channels open since they open only when the inside of
the membrane is at its maximum positive charge Positively charged potassium ions flow rapidly out of the muscle cell following
their concentration gradient this decreases the level of positive
charge inside the sarcolemma. This return of the
membrane to resting levels of charge is called repolarization. Once the
sarcolemma has been fully repolarized the potassium channels close. A sodium
potassium pump uses ATP energy to restore the
concentration gradient of sodium and potassium to their normal
levels

7 Replies to “Action Potential Generation in Skeletal Muscle”

  1. I think there might be a mistake here. The reason for the opening of the Potassium channels is not the depolarization of the cell, but the action potential. The same one that opened the Sodium channels also opens the Potassium channels, it just takes them a longer time to open.

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