Resting Membrane Potential

Question 1

Define resting membrane potential and its typical value in a nerve cell.

Answer 1

Resting membrane potential – voltage measured across the plasma membrane of an excitable
cell at rest (-70mV)

Question 2

What conditions create this resting membrane potential?

Answer 2

Permeability of the plasma membrane and the operation of the sodium potassium pump (ATP pump)

Question 3

Which ions are greater in concentration outside the cell….greater inside the cell?

Answer 3

sodium is greater in concentration outside the
cell and Potassium is greater in concentration inside the cell

Question 4

Why is the Na/K pump so important?

Answer 4

Keeps the concentration gradient the same, pumps in or out exact amount leaked through open channels

Question 5

Explain what depolarization, repolarization and hyperpolarization mean. What happens from an ion perspective during each of these phases? (What goes into/out of the cell during each phase)

Answer 5

Depolarization – it is becoming positive (Na+ goes in the cell)

• Repolarization – the cell is becoming negative (K+ goes in and Na+ comes out)
• Hyperpolarization – the cell became more negative than resting potential