PHGY 209 Lecture : PHGY 209 Nerves and synapses.doc

• School: McGill University
• Department: Physiology
• Course: PHGY 209
• Professor: Ann Wechsler

Document Summary

[ not a single atom that is in your body today was there when that event took place steve grand (computer scientist)] Spinal cord=highway of processing information (relaying up to brain and down to periphery of body) and mediates automated activities (ex. walking) Afferent fibers or sensory neurons bring information from periphery to spinal cord (ex. skin sensations) Neurons use electricity to propagate information from a place to another. There is probably from a hundred trillion to a quadrillion of synapses in human nerv. syst. Soma: cell body, containing nucleus, where metabolic and synthetic activities take place, maintaining neuron in living state. Dendrites: antennas of neuron, for information to flow in. Axon: unique, for information to flow out (initial segment inserts in cell soma, presynaptic terminal=swelling at axon"s end) Resting membrane potential: the inside of a neuron has a slightly negative voltage(=electrical pressure) compared to the outside (-60mv to -70mv, tiny fraction of unpaired negatives charges, less than 1%).