Which ion largely sets the resting membrane potential of neurons and muscle cells?

Study for the Paramedic Aandamp;P Exam. Engage with flashcards and multiple choice questions, complete with hints and explanations. Prepare effectively for your exam!

Multiple Choice

Which ion largely sets the resting membrane potential of neurons and muscle cells?

Potassium largely sets the resting membrane potential because the membrane is most permeable to K+ when a cell is at rest. Potassium ions leak out through K+ channels, and as they move out, the inside becomes more negative until the chemical gradient and electrical gradient balance. This makes the resting potential sit near the potassium equilibrium potential (around -90 mV), which is very negative. Sodium and calcium have gradients too, but the membrane is far less permeable to them at rest, so they contribute little to establishing the resting potential. Magnesium isn’t a major player in setting this potential either. The sodium–potassium pump maintains the gradients by moving Na+ out and K+ in, but it’s the leak conductance to potassium that largely determines the resting membrane potential.

Potassium largely sets the resting membrane potential because the membrane is most permeable to K+ when a cell is at rest. Potassium ions leak out through K+ channels, and as they move out, the inside becomes more negative until the chemical gradient and electrical gradient balance. This makes the resting potential sit near the potassium equilibrium potential (around -90 mV), which is very negative. Sodium and calcium have gradients too, but the membrane is far less permeable to them at rest, so they contribute little to establishing the resting potential. Magnesium isn’t a major player in setting this potential either. The sodium–potassium pump maintains the gradients by moving Na+ out and K+ in, but it’s the leak conductance to potassium that largely determines the resting membrane potential.

More practice questions