NROB60H3 Chapter 3: The Neuronal Membrane at Rest
Document Summary
Simple reflex: must collect distribute and integrate information. Axon carry ions not free electrons, therefore cytosol less conductive than a copper wire, also less insulated. Action potential: nerve impulse with fixed size and duration, frequency and distribution codes information; brief reversal in potential. Excitable membrane: cells capable of generating and conducting action potentials; muscle and nerve cells. Resting potential difference: difference in electrical charge across the membrane; negative. Water: polar: effective solvent of other polar molecules. Lipid: water insoluble, barrier to water soluble ions and water: phospholipid: polar phosphate head and non polar hydrocarbon tail, phospholipid bilayer: two layers of phospholipids that isolates cytosol from extracellular environment. Channel proteins: protein chemically heterogeneous so hydrophobic in bilayer and hydrophilic on either side. Ion selectivity: based on diameter of pore and nature of r groups lining it: gating: Ion pumps: membrane spanning proteins use atp to move ions across membrane, ex. pump ca2+ and na+