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All cardiac muscle cells are electrically linked to one another, by intercalated discs which allow the action potential to pass from one cell to the next. [1][2] This means that all atrial cells can contract together, and then all ventricular cells. Different shapes of the cardiac action potential in various parts of the heart.
However, other ions such as calcium may be important and there is a great diversity of channels for all ions. [2] As an example, the cardiac action potential illustrates how differently shaped action potentials can be generated on membranes with voltage-sensitive calcium channels and different types of sodium/potassium channels. The second type ...
The sinoatrial node (also known as the sinuatrial node, SA node or sinus node) is an oval shaped region of special cardiac muscle in the upper back wall of the right atrium made up of cells known as pacemaker cells. The sinus node is approximately 15 mm long, 3 mm wide, and 1 mm thick, located directly below and to the side of the superior vena ...
Action potentials are considerably different between conductive and contractive cardiomyocytes. While sodium Na + and potassium K + ions play essential roles, calcium ions Ca 2+ are also critical for both types of cell. Unlike skeletal muscles and neurons, cardiac conductive cells do not have a stable resting potential.
Cardiac excitation-contraction coupling (Cardiac EC coupling) describes the series of events, from the production of an electrical impulse (action potential) to the contraction of muscles in the heart. [1] This process is of vital importance as it allows for the heart to beat in a controlled manner, without the need for conscious input.
In electrocardiography, the atrial action potential are action potentials that occur in the heart atrium. They are similar to ventricular action potential with the exception of having a more narrow phase 2 (plateau phase) due to a smaller calcium influx. Also, in comparison to the ventricular action potential, atrial action potentials have a ...
Pacemaker potential. In the pacemaking cells of the heart (e.g., the sinoatrial node), the pacemaker potential (also called the pacemaker current) is the 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.
I to1 is active during phase 1, causing a fast repolarization of the action potential. The cardiac transient outward potassium current (referred to as Ito1 or Ito[1] ) is 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.