What is the resting membrane potential of a cardiac cell?

What is the resting membrane potential of a cardiac cell?

• A. About -50 mV
• B. About -70 mV
• C. About -90 mV
• D. About -60 mV

Answer: (B)

The resting membrane potential of a cardiac cell is approximately -90 mV. This value is significant because it reflects the ionic concentration gradients across the cell membrane, primarily maintained by the sodium-potassium ATPase pump. In cardiac cells, the high permeability to potassium ions when the cell is at rest contributes to this negative charge inside the cell, as potassium tends to diffuse out of the cell, leaving behind negatively charged proteins and ions. While -70 mV, which is the choice provided, is closer to the resting potentials seen in neuronal cells, cardiac cells exhibit a more negative resting potential due to the unique ionic dynamics involved, which promote a resting state that is even more negative. The difference in resting membrane potential between cardiac and neuronal cells is essential for their respective functions, particularly in the generation and propagation of action potentials in cardiac tissue.

The resting membrane potential of a cardiac cell is approximately -90 mV. This value is significant because it reflects the ionic concentration gradients across the cell membrane, primarily maintained by the sodium-potassium ATPase pump. In cardiac cells, the high permeability to potassium ions when the cell is at rest contributes to this negative charge inside the cell, as potassium tends to diffuse out of the cell, leaving behind negatively charged proteins and ions.

While -70 mV, which is the choice provided, is closer to the resting potentials seen in neuronal cells, cardiac cells exhibit a more negative resting potential due to the unique ionic dynamics involved, which promote a resting state that is even more negative. The difference in resting membrane potential between cardiac and neuronal cells is essential for their respective functions, particularly in the generation and propagation of action potentials in cardiac tissue.