PSYC 1000 Lecture Notes - Lecture 9: Resting Potential, Membrane Potential, Action Potential

• School: Memorial University
• Department: Psychology
• Course: PSYC 1000
• Professor: Elizabeth Russell

Document Summary

Brief moments between the times the neuron fires. A (cid:374)euro(cid:374) at (cid:862)rest(cid:863) is a(cid:272)tuall(cid:455) polarized. Negatively charged inside compared to outside (approximately -70mv) Resting membrane potential is needed for action potential to occur: these conditions must be established before the neuron can fire. Action potential (cid:862)voltage-gated(cid:863) na+ a(cid:374)d k+ io(cid:374) (cid:272)ha(cid:374)(cid:374)els are prese(cid:374)t alo(cid:374)g a(cid:454)o(cid:374: open and close according to the membrane polarity. In response to other neurons, a neuron may become depolarized (gets less negative on inside: the voltage-gated channels open when the neuron becomes depolarized. If neurons reach -55mv (firing threshold) na+ channels suddenly open leading to influx of na+ Inside of cell goes from -55mv to +30mv (reversal of polarity) At +30 mv, na+ channels (which were open) close and k+ channels open (which were closed) leading to efflux of k+ and na+ and repolarization occurs. Na+ channels open to let na+ ions flow into the neuron.