explain about the sodium potassium pump !
At resting stage of a neuron:
Axonal membrane is more permeable to K+ and nearly impermeable to Na+.It is impermeable to negatively charged proteins present inside the axoplasm. Thus, it does not let them go out.
As a result, the axoplasm has more concentration of K+ and negatively charged proteins, and less concentration of Na+. This creates a concentration gradient.
Gradient is maintained by the Sodium-Potassium Pump which pumps 3 Na+ out and 2 K+ in.
It was found that theconcentrations
of sodium andpotassium ions
on the two other sides of the membrane are interdependent, suggesting that the same carrier transports both ions. It is now known that the carrier is an ATP-ase and that it pumps three sodium ions out of the cell for every two potassium ions pumped in.
The Na+/K+-ATPase helps maintain resting potential, avail transport and regulate cellular volume. To maintain thecell membrane
potential, cells must keep a low concentration of sodium ions and high levels of potassium ions within the cell . After the action potential is formed, when the cell is re-polarizing, that is within the cell it is becoming more and more negative as K+ ions flood out, there is a stage where the membrane potential undershoots its resting membrane potential as K+ channels take too long to close. This is called hyper-polarization. In order to restore the appropriate concentrations, the sodium-potassium pump pumps 3 sodium ions out by hydrolysing ATP and allows 2 potassium ions in through active transport. The result is resting membrane potential restoration and another action potential can happen again.
So , It uses ATP-ase and that it pumps three sodium ions out of the cell for every two potassium ions pumped in.