In muscle cells, resting membrane potential is equal to the isoelectric potential of

The isoelectric potential of Cl- is -70mV and of K+ is -90mV. According to ‘Ganong’ and ‘Principles of Medical Physiology’, the actual measured RMP of a nerve fibre is -70mV rather than the calculated value of -90mV. So in nerve fibres, the RMP is equal to or closer to the isoelectric potential of Cl-. Whereas in muscle cells, the RMP is -90mV, which is equal to the isoelectric potential of K+.