Low resistance gap junctions allow for what crucial phenomenon in cardiac tissue?

• A. Current leakage
• B. Active transport of ions
• C. Electrical isolation of cells
• D. No conduction across cells

Answer: (A)

Low resistance gap junctions create direct electrical coupling between neighboring cardiomyocytes. This means ions can flow freely from one cell to the next, so when one cell depolarizes, current leaks through these junctions into its neighbor and triggers rapid depolarization there as well. This electrotonic spread allows the action potential to propagate quickly and synchronously through the heart muscle.

Active transport of ions requires pumps and occurs across the cell membrane, not directly between cells. Electrical isolation or no conduction across cells would imply high resistance or closed junctions, which is the opposite of what low-resistance gap junctions provide.