Polarization of the membrane is considered what state?

Polarization of the membrane is considered what state?

• A. resting
• B. refractory
• C. repolarized
• D. action potential

Answer: (A)

Polarization refers to a membrane in which there is a voltage difference across it, with the inside more negative than the outside. This is the resting membrane potential, the steady, baseline state of a neuron or muscle cell. It exists because ions are distributed unevenly across the membrane and the membrane is more permeable to certain ions (notably K+ at rest) and because the Na+/K+ pump helps maintain those gradients. Because of this separation of charge across the membrane, the cell is considered polarized. When a stimulus occurs, voltage-gated channels open and positive ions rush in, making the inside less negative; that change is depolarization, which, if strong enough, leads to an action potential. After the peak, the membrane restores its negative interior by expelling K+, a process called repolarization. The period right after an action potential where the cell is harder (or impossible) to excite is the refractory period, not a polarized state. So the membrane’s polarization corresponds to the resting state.

Polarization refers to a membrane in which there is a voltage difference across it, with the inside more negative than the outside. This is the resting membrane potential, the steady, baseline state of a neuron or muscle cell. It exists because ions are distributed unevenly across the membrane and the membrane is more permeable to certain ions (notably K+ at rest) and because the Na+/K+ pump helps maintain those gradients. Because of this separation of charge across the membrane, the cell is considered polarized.

When a stimulus occurs, voltage-gated channels open and positive ions rush in, making the inside less negative; that change is depolarization, which, if strong enough, leads to an action potential. After the peak, the membrane restores its negative interior by expelling K+, a process called repolarization. The period right after an action potential where the cell is harder (or impossible) to excite is the refractory period, not a polarized state. So the membrane’s polarization corresponds to the resting state.