What is the process by which ATP used to move sodium ions out of cell and potassium back into completely restores resting conditions neuron?
The resting potential is the difference in electrical potential between the inside and outside of a cell. In neurons, this is maintained at around -70 millivolts. When a neuron is stimulated, the sodium-potassium pump is inhibited and sodium ions flood into the cell. This causes the membrane potential to become less negative, and eventually it can reach a threshold potential at which the neuron fires an action potential.
After the action potential, the sodium-potassium pump is activated and it begins to pump sodium ions out of the cell and potassium ions back in. This process gradually restores the resting potential.
Steps involved
1. The first step is the binding of three sodium ions to the extracellular side of the pump. This causes a conformational change in the protein that exposes the binding sites on the intracellular side of the pump.
2. Two potassium ions then bind to these sites, and this causes another conformational change in the protein. This change in shape is what actually moves the ions across the membrane.
3. The final step is the hydrolysis of ATP to ADP. This provides the energy needed to complete the transport cycle.
The sodium-potassium pump is a critical component of the body's ability to maintain homeostasis. By regulating the concentrations of sodium and potassium ions in the blood, the pump helps to control the body's fluid balance and blood pressure. It also plays a role in muscle contraction, nerve transmission, and other important cellular functions.