BIOL 171 Lecture Notes - Lecture 9: Threshold Potential, Semipermeable Membrane, Volt
Document Summary
Neuronal electrophysiology neurons produce two types of electric signals propagated action potentials that can travel long distances local graded potentials that do not spread from their site of formation different in size; don"t spread far down axon. Potential difference separation of charge (positive and negative separated; like battery ends) measured in volts (v) in living cells: charges (ions) are separated by semi-permeable membrane. 2 positively charged ions to create potential difference (na+ and k+) ions flow through ion channel in the cell membrane (charged particles cannot cross membrane) potential differences are measured in millivolts (mv) Resting membrane potential potential difference measured across the cell membrane of an unstimulated (resting) nerve cell normally -60mv to -70mv resting membrane potential = -70mv result of different composition of icf (k+ and proteins) compared to. Potassium-sodium pump helps even charge out by pumping in 2 k+ and pumping out 3 na+
