Final answer:
Increasing sodium permeability results in depolarization, moving the membrane potential towards a positive value, and is crucial for generating an action potential in nerve cells.
Step-by-step explanation:
Increasing sodium permeability from rest would lead to a change in membrane potential known as depolarization. When the Na+ channels open, Na+ ions, which are in higher concentration outside the cell, will rush in. This influx of positively charged ions causes the inside of the cell to become less negative, moving the membrane potential toward zero and even becoming positive, reaching up to +30 mV. This process is driven by both the concentration gradient and the electrical gradient, with the negatively charged proteins under the membrane also attracting the Na+ ions.
During depolarization, other voltage-gated channels begin to open, which leads to further changes in the membrane potential. Subsequently, potassium channels open, allowing K+ ions to leave the cell, starting the process of repolarization, whereby the cell's membrane potential returns to its resting state of around -70 mV. This sequence of ion movements and channel openings is essential in the generation of an action potential, which is a fundamental process in nerve impulse transmission.