ANP 1106 Lecture Notes - Lecture 6: Resting Potential, Cell Membrane, Neurotransmitter Receptor

• School: University of Ottawa
• Department: Anatomy and Physiology
• Course: ANP 1106
• Professor: Frank Feiner

Document Summary

Nervous system fundamentals: cytoplasm inside plasma membrane positively charged relative to outside. Graded potentials: brief, short-distance signals, graded: size/distance varies with stimulus strength, aka receptor/generator (eg heat/light -> sensory receptor) or. Postsynaptic (neurotransmitter crosses synapse-> membrane receptor: current flows in all directions, but dies out within a few mm of its origin, gps essential in initiating long-distance aps. Ap spike drops: events during hyperpolarization, k+ continues to leave cell, lasting longer than needed, hyperpolarization results: membrane potential drops to slightly below resting state levels, to restore resting intra/extracellular [na+] and [k+] requires the na+-k+ Atpase pump, ie. energy expenditure (atp->adp: propagation (spreading) of an action potential, can only move forward, ie away from impulse origin, right after ap fires, na+ channels closed/inactivated. Has many synaptic vesicles, each filled with thousands of nts: neurotransmitter receptor region on postsynaptic neuron"s, huge ~40 nm synaptic cleft/gap in between (fluid-filled) membrane (cell body/dendrite, nt size ~ 1 nm, nerve impulses not transmitted directly cell-to-cell.