Unlike Ion Channels, which are a passive transport mechanism, Ion Pumps are active transport mechanisms that use ATP to move ions against their concentration gradient. This is essential for maintaining the resting membrane potential and the overall ionic balance of the cell.
In Neuroscience Ion Pumps are of paticular importance as they are responsible for the phenomena of neural excitability.
Some notable ion pumps include:
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The Sodium-Potassium Pump (Na+/K+ ATPase):
- This pump moves 3 Na+ ions out of the cell and 2 K+ ions into the cell, using one ATP molecule. This creates a net negative charge inside the cell, contributing to the resting membrane potential.
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Calcium Pump (Ca2+ ATPase):
- this pump moves Ca2+ ions out of the cell, which is crucial for maintaining low intracellular calcium levels. It plays a key role in muscle contraction and neurotransmitter release.
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Hydrogen Pump (H+ ATPase):
- This pump moves H+ ions across the membrane, which is important for maintaining pH balance and creating electrochemical gradients.