If the axo-membrane becomes more permeable to potassium Ions. What would happen?
If the axo-membrane becomes more permeable to potassium ions, it would lead to an increase in the flow of potassium ions across the cell membrane. This change in permeability would have several impacts on the cell.
1. Resting Membrane Potential: The resting membrane potential of a cell is a measure of the electrical charge difference across the cell membrane when the cell is at rest. Normally, the resting membrane potential of a neuron is around -70 millivolts (mV), with higher concentrations of positively charged ions outside the cell and higher concentrations of negatively charged ions inside the cell. The increased permeability to potassium ions would result in an efflux or outward flow of these positively charged ions, which would make the inside of the cell more negative. As a result, the resting membrane potential would become less negative (closer to zero), leading to depolarization.
2. Electrical Signal Generation: Neurons use changes in membrane potential to generate electrical signals (action potentials) that allow communication between cells. By making the axo-membrane more permeable to potassium ions, it would favor the exit of positively charged potassium ions from the cell. This efflux of positive charge would reduce the overall positive charge inside the cell and therefore decrease the likelihood of generating an action potential. In other words, the increased potassium permeability would make it more difficult for the cell to generate an electrical signal.
3. Cell Excitability and Repolarization: During an action potential, the cell depolarizes (becomes less negative) by allowing an influx of sodium ions followed by repolarization (becoming more negative again) through the efflux of potassium ions. If the axo-membrane becomes more permeable to potassium ions, repolarization would be facilitated. This means that after an action potential, the cell would return to its resting state more quickly as the potassium ions would exit the cell more readily, restoring the original resting membrane potential and preparing the cell for another action potential.
Overall, an increase in the permeability of the axo-membrane to potassium ions would lead to changes in the resting potential, electrical signal generation, and repolarization of the cell. These changes can affect the excitability and function of the neuron.