DASC20010 Lecture Notes - Lecture 3: Axon Hillock, Axon Terminal, Postsynaptic Potential
5 Aug 2018
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Objectives of this lecture: describe the neuron, explain graded potentials, explain action potentials, explain the ways the action potential is propagated, describe synaptic transmission. Trigger events: specialised nerve endings, change in electrical field, chemical messengers. Spread of graded potential: typically doesn"t spread, movement of activity up the nerve- must be fast has to travel a long way. Not explained by graded potential: doesn"t explain the propagation of a neuron- but explains the start. Voltage gated pumps: open & close these channels- triggered by changes in voltage- caused by changes in permeability. Action potential (resting: resting potential: all voltage-gated channels closed. Action potential (graded potential: at threshold- na+ activation gate opens and pna+ rises, only operates at a very small range. & changes voltage at a very small amount: needs to change to rise of about 20 mili volts, when it gets to -50 causes changes to voltage-gated ion channels- opens up.
