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The ion pump most relevant to the action potential is the sodium–potassium pump, which transports three sodium ions out of the cell and two potassium ions in. [13] [14] As a consequence, the concentration of potassium ions K + inside the neuron is roughly 30-fold larger than the outside concentration, whereas the sodium concentration outside ...
The sodium–potassium pump (sodium–potassium adenosine triphosphatase, also known as Na + /K +-ATPase, Na + /K + pump, or sodium–potassium ATPase) is an enzyme (an electrogenic transmembrane ATPase) found in the membrane of all animal cells. It performs several functions in cell physiology. The Na + /K +-ATPase enzyme is active (i.e. it ...
An example is the sodium-calcium exchanger or antiporter, which allows three sodium ions into the cell to transport one calcium out. [24] This antiporter mechanism is important within the membranes of cardiac muscle cells in order to keep the calcium concentration in the cytoplasm low. [ 9 ]
Key: a) Sodium (Na +) ion. b) Potassium (K +) ion. c) Sodium channel. d) Potassium channel. e) Sodium-potassium pump. In the stages of an action potential, the permeability of the membrane of the neuron changes. At the resting state (1), sodium and potassium ions have limited
Voltage-gated ion-channels are usually ion-specific, and channels specific to sodium (Na +), potassium (K +), calcium (Ca 2+), and chloride (Cl −) ions have been identified. [1] The opening and closing of the channels are triggered by changing ion concentration, and hence charge gradient, between the sides of the cell membrane. [2]
By pumping three positively charged sodium ions (Na +) out of the cell for every two positively charged potassium ions (K +) pumped into the cell, not only is the resting potential of the cell established, but an unfavorable concentration gradient is created by increasing the concentration of sodium outside the cell and increasing the ...
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If there are unequal concentrations of an ion across a permeable membrane, the ion will move across the membrane from the area of higher concentration to the area of lower concentration through simple diffusion. Ions also carry an electric charge that forms an electric potential across a membrane. If there is an unequal distribution of charges ...