Cardiac action potential
Brief change in voltage across the cell membrane of heart cells.- Cardiac action potential
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Action potential occurs when the membrane potential of a specific cell location rapidly rises and falls.
In cardiac muscle cells, on the other hand, an initial fast sodium spike provides a "primer" to provoke the rapid onset of a calcium spike, which then produces muscle contraction.
Potassium channels are the most widely distributed type of ion channel and are found in virtually all living organisms.
By contributing to the regulation of the cardiac action potential duration in cardiac muscle, malfunction of potassium channels may cause life-threatening arrhythmias.
Group of cells known as pacemaker cells, located in the wall of the right atrium of the heart.
This resting phase (see cardiac action potential, phase 4) ends when an action potential reaches the cell.
One of three types of vertebrate muscle tissue, with the other two being skeletal muscle and smooth muscle.
Electrical stimulation in the form of a cardiac action potential triggers the release of calcium from the cell's internal calcium store, the sarcoplasmic reticulum.
Too fast or too slow.
The first of arrhythmia is a result of enhanced or abnormal impulse formation originating at the pacemaker or the His-Purkinje network.
Gene that codes for a protein known as Kv11.1, the alpha subunit of a potassium ion channel.
This ion channel (sometimes simply denoted as 'hERG') is best known for its contribution to the electrical activity of the heart: the hERG channel mediates the repolarizing IKr current in the cardiac action potential, which helps coordinate the heart's beating.
Antiporter membrane protein that removes calcium from cells.
The ability for the Na+/Ca2+ exchanger to reverse direction of flow manifests itself during the cardiac action potential.
The Purkinje fibers (often incorrectly ; Purkinje tissue or subendocardial branches) are located in the inner ventricular walls of the heart, just beneath the endocardium in a space called the subendocardium.
They conduct cardiac action potentials more quickly and efficiently than any other cells in the heart.
Slow, positive increase in voltage across the cell's membrane (the membrane potential) that occurs between the end of one action potential and the beginning of the next action potential.
This increase in membrane potential is what causes the cell membrane, which typically maintains a resting membrane potential of -70 mV, to reach the threshold potential and consequently fire the next action potential; thus, the pacemaker potential is what drives the self-generated rhythmic firing (automaticity) of pacemaker cells, and the rate of change (i.e., the slope) of the pacemaker potential is what determines the timing of the next action potential and thus the intrinsic firing rate of the cell.
One of the ion currents across the cell membrane of heart muscle cells.
It is the main contributing current during the repolarizing phase 1 of the cardiac action potential.