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Be able to walk through the steps of an action potential in terms SHORT LIVED DISRUPTIONS IN THE MEMBRANE POTENTIALS AND ARE THE ACTUAL SIGNALS THAT MOVE ACROSS THE AXON▪of how membrane potential is changing at each step
THE GRADED POTENTIALS THAT MAKE THE MEMBRANE LESS NEGATIVE ARE DEPOLARIZING AND THE GRADED POTENTIALS THE MAKE THE MEMBRANE MORE NEGATIVE ARE THE HYPERPOLARIZING ▪What channels are being opened/ closedVOLTAGE GATED ION CHANNELS▪What ions are in/ out of the cellSODIUM IN AND POTASSIUM OUT▪Be able to identify resting membrane potential, action potential, and refractory period on a graph (and identify the above points in relation to that graph) RESTING IS -70 ACTION IS -55oSodium channels ▪What are their 2 gates, when are they open, closed? SODIUM AND POTASSIUMoWhy do you need the sodium potassium pump? RESTORE ION CONCENTRATIONS TO THEIR EQUILIBRIUM STATES, THUS THE SODIUM ACTIVATION GATE CLOSES AND THE INACTIVATION GATE REOPENSoThe action potential is a passive process. Why do you still need energy to make it run (where does that energy go?) THE THRESHOLD HAS TO BE REACHED, RESTING MEMBRANE POTENTIAL IS MAINTAINED BY THE SODIUM POTASSIUM PUMP WHICH REQUIRES ATPoHow do action potentials compare to graded potentials? THEY DO NOT ADD TOGETHER OR INFER WITH EACH OTHER●Propagation of action potentialPROPAGATION- THE MOVEMENT OF AN ACTION POTENTIAL DOWN THE AXONoBe familiar with how this works, how the sodium channels help ensure the action potential can only fire one way THE INFLUX OF SODIUM IONS DURING THE RISING PHASE OF THE ACTION POTENTIAL DEPOLARIZES THE ADJACENT MEMBRANE TO THRESHOLD TRIGGERING ANOTHER ACTION POTENTIAL, BECAUSE THE VOLTAGE GATED SODIUM CHANNELS THAT ADJUST FIRE ARE INACTIVE DURING THE REFRACTORY PERIOD oUnderstand what saltatory conduction is IN MYELINATEDAXONS ARE ONLY GENERATED IN THE NODES BECAUSETHIS IS THE ONLY PLACE WHERE THE IONS ARE EXPOSED TO THEENVIRONMENT, WHEN THE ACTION POTENTIALS JUMPoWhat are the two ways to speed up the rate of an action potential? INCREASE THE DIAMETER OF THE AXONoBe able to look at a chart of myelination and axon diameter and be able to predict whichaxon will pass the signal along the fastest. ●SynapsesoWhat 2 types of cells do you need at a synapse? PRE AND POST SYNAPTIC CELLWhat aretheir roles?PRE- TRANSMITS THE ACTION POTENTIAL TO THE SYNAPSE POST- RECEIVES THE SIGNALoWhat are the two types of synapses? ELECTRICAL- GAP JUNCTIONS AND CHEMICAL Which one is more common in vertebrates? CHEMICALoChemical synapses▪Be familiar with synaptic cleftGAP BETWEEN THE PRE AND POSTSYNAPTIC CELL, synaptic vesicles CONTAINNEUROTRANSMITTERS- CHEMICAL LIGANDS THAT
CARRY THE MESSAGE ACROSS THE SYNAPSE,voltage gated Ca2+channels THESE OPEN AND CAUSE AN INFLUX OF CALCIUM IONS (PLAY A ROLE IN THE FUSION OF THE THE SYNAPTIC VESICLES,and postsynapticreceptors OPENS GATED CHANNEL INFLUX OF SODIUM IONSand how these play together to pass the