In hypokalemia, what happens to the duration of depolarization?

In hypokalemia, there is a decrease in serum potassium levels, which has a significant impact on the electrical activity of cells, particularly in cardiac and neuromuscular tissues. Potassium is crucial for maintaining resting membrane potential and the normal repolarization phases of action potentials.

When potassium levels are low, the resting membrane potential becomes more negative (hyperpolarized), requiring a larger influx of sodium to reach the threshold for depolarization. Consequently, the duration of depolarization is extended. This results in a prolonged action potential, as the time taken for the membrane to return to a resting state is lengthened. This prolonged depolarization can also manifest as longer QT intervals on an electrocardiogram, which is a critical finding in patients with hypokalemia.

In summary, the correct answer illustrates that hypokalemia prolongs the duration of depolarization because the altered ion concentrations affect the dynamics of action potential generation and conduction within excitable tissues.