Exploring the resting membrane potential
How is the resting membrane potential established?
Voltmeter · recording − reference
● K⁺■ Na⁺◆ Cl⁻Protein⁻ (inside)
Na⁺/K⁺ ATPase: each ATP-powered cycle moves 3 Na⁺ out and 2 K⁺ in, helping maintain high Na⁺ outside and high K⁺ inside. Pump motion is illustrative; concentrations are held at your selected values.
Visible ions and protein charges are illustrative. Their numbers and crossings do not represent the actual fraction of ions that must move. Only a tiny fraction moves to establish the voltage; bulk solutions remain nearly electrically neutral.
Measured voltage
Insert the electrode to measure Vm
Insert the electrode to measure Vm
−100−500+70 mVEKENaECl