Cardiac Muscle Contraction

Cardiac Muscle Contraction - Cardiac Muscle Contraction

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Cardiac Muscle Contraction The sarcolemma (plasma membrane) of an unstimulated muscle cell is polarized—that is, the inside  of the sarcolemma is negatively charged with respect to the outside. The unstimulated state of the  muscle cell, called the resting potential, is created by the presence of large, negatively charged  proteins and nucleic acids inside the cell. A balance between K +  inside the cell and Na +  outside the  cell contributes to the polarization. During an action potential, the balance of Na +  and K +  is upset so  that the cell becomes depolarized. The series of events that occurs during and following an action  potential in contractile muscle fibers of the heart is similar to that in skeletal muscle. Here is a  description of these events:  Rapid depolarization occurs when fast-opening Na +  channels in the sarcolemma open and  allow an influx of Na
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This note was uploaded on 11/10/2011 for the course PT 101 taught by Professor Staff during the Spring '10 term at Texas State.

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