Which statement best describes the phase of the cardiac cell cycle described as polarization, preparing for discharge?

Which statement best describes the phase of the cardiac cell cycle described as polarization, preparing for discharge?

• A. Depolarization
• B. Repolarization
• C. Resting state
• D. Polarization of the cell, preparing it for discharge

Answer: (D)

Before a cardiac cell fires, its membrane is polarized, meaning the inside is negatively charged compared with the outside. This resting membrane potential primes the cell to respond to a stimulus. When a trigger arrives, the cell depolarizes as sodium rushes in, producing the actual discharge (the action potential). Afterward, repolarization restores the negative interior, returning the cell to its polarized, ready-to-fire state. So describing polarization as the cell’s state preparing for discharge fits the pre-fire, ready state. The other terms describe the discharge itself (depolarization) or the return to baseline after discharge (repolarization).

Before a cardiac cell fires, its membrane is polarized, meaning the inside is negatively charged compared with the outside. This resting membrane potential primes the cell to respond to a stimulus. When a trigger arrives, the cell depolarizes as sodium rushes in, producing the actual discharge (the action potential). Afterward, repolarization restores the negative interior, returning the cell to its polarized, ready-to-fire state. So describing polarization as the cell’s state preparing for discharge fits the pre-fire, ready state. The other terms describe the discharge itself (depolarization) or the return to baseline after discharge (repolarization).