Question

For a resting potential in a cardiac cell to exist, there must be an:

A) adequate number of potassium ions inside the cell and sodium ions
outside the cell.

B) adequate number of sodium ions inside the cell and potassium ions outside the cell.

C) influx of calcium ions into the cell.

D) ionic equilibrium between the inside and outside of the cell.

Answer 1

For a resting potential in a cardiac cell, there must be more potassium ions inside and sodium ions outside of the cell. The sodium-potassium pump maintains this imbalance, which is crucial for the resting membrane potential.

Step-by-step explanation:

For a resting potential in a cardiac cell to exist, there must be an adequate number of potassium ions inside the cell and sodium ions outside the cell. This is consistent with the known physiology of cells, where a neuron at rest is negatively charged due to a high concentration of potassium ions (K+) inside, and a high concentration of sodium ions (Na+) outside the cell. The resting membrane potential, approximately -70 mV, is maintained by the selective permeability of the cell membrane to these ions and the action of the sodium-potassium pump. This pump actively transports 3 Na+ ions out of the cell and 2 K+ ions into the cell against their respective concentration gradients, using ATP as an energy source.