What does it mean when a nerve cell is described as polarized?

When a nerve cell is described as polarized, it indicates that there is an uneven distribution of ions across the cell membrane, leading to a charge difference. Specifically, a polarized nerve cell has more positive ions, such as sodium (Na+), outside the cell and more negative ions, such as potassium (K+), inside the cell. This situation creates a negative charge inside relative to the outside of the cell, which is crucial for the transmission of electrical signals in the nervous system.

This polarization is vital for the cell's ability to generate action potentials, which are the electrical impulses that propagate along the nerve fibers. The uneven distribution of ions is maintained by various mechanisms, including the sodium-potassium pump, which actively transports sodium out of the cell and potassium into it, thus sustaining the polarized state.

The other options do not accurately describe the state of a polarized nerve cell. A state of equal distribution of ions would indicate that the cell is at resting potential, not polarized. Furthermore, having more negative ions outside than inside does not correspond to polarization, as it would not create the required charge difference. Lastly, depolarization refers to a state where the polarization is reduced, making the inside of the cell less negative or even positive, which is the opposite