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The sodium-calcium exchanger ionic pump works to pump calcium out of the intracellular space, thus effectively relaxing the cell. The sodium/potassium pump restores ion concentrations of sodium and potassium ions by pumping sodium out of the cell and pumping (exchanging) potassium into the cell. Restoring these ion concentrations is vital ...
Ionic pumps as discussed above, like the sodium-calcium exchanger and the sodium-potassium pump restore ion concentrations back to balanced states pre-action potential. This means that the intracellular calcium is pumped out, which was responsible for cardiac myocyte contraction. Once this is lost, the contraction stops and the heart muscles relax.
The sodium-calcium exchanger (which allows 3 Na + to flow down its electrochemical gradient in exchange for 1 Ca ++ ion to flow out of the cell) works to decrease the levels of intracellular calcium. As the heart rate becomes more robust, and the length of diastole decreases, the Na + /K +-ATPase, which removes the Na + brought into the cell by ...
The main pumps involved are: the sarcoplasmic reticulum Ca 2+-ATPase, which pumps Ca 2+ back into the SR, the Sarcolemmal sodium-calcium exchanger, which pumps one Ca 2+ out of the cell, in exchange for 3 sodium ions being pumped into the cell, the Sarcolemmal Ca 2+-ATPase, which uses ATP to pump Ca 2+ directly out of the cell and the ...
A slow heart rate of 60 or less beats per minute is defined as bradycardia. A fast heart rate of more than 100 beats per minute is defined as tachycardia. An arrhythmia is defined as one that is not physiological such as the lowered heart rate that a trained athlete may naturally have developed; the resting heart rates may be less than 60 bpm.
The funny current is highly expressed in spontaneously active cardiac regions, such as the sinoatrial node (SAN, the natural pacemaker region), the atrioventricular node (AVN) and the Purkinje fibres of conduction tissue. The funny current is a mixed sodium–potassium current that activates upon hyperpolarization at voltages in the diastolic ...
HCN4 is the main isoform expressed in the sinoatrial node, but low levels of HCN1 and HCN2 have also been reported.The current through HCN channels, called the pacemaker current (I f), plays a key role in the generation and modulation of cardiac rhythmicity, [13] as they are responsible for the spontaneous depolarization in pacemaker action potentials in the heart.
Cardiac physiology or heart function is the study of healthy, unimpaired function of the heart: involving blood flow; myocardium structure; the electrical conduction system of the heart; the cardiac cycle and cardiac output and how these interact and depend on one another.