Action Potentials and Neuronal Electrophysiology, Quizzes of Biology

Download Action Potentials and Neuronal Electrophysiology and more Quizzes Biology in PDF only on Docsity! TERM 1 Action Potential DEFINITION 1 (Not size, but number of GP)Electrical signal, long range, in neurons and muscleActivated by graded potentialsAP's do not degrade over time and distance TERM 2 Voltage - Gated Channels DEFINITION 2 (across the membrane)Opens when membranes reach particular voltageUsually ~15-20 mV above resting potentialAll channels open together, causing action potential to occurEnter inactivated state soon after opening, making refractory period TERM 3 PHASES OF AP DEFINITION 3 (controlled by different open channels) TERM 4 Depolarization to Threshold (1) DEFINITION 4 FIRING LEVELChemical or mechanical gated Na+ channels openNa+ enters down gradientt= threshold, here all V-gated Na+ channels openTTX (drug) blocks fast V-gated Na+ channels TERM 5 AP Spike (2) DEFINITION 5 All AP's in one neuron are identical Na+ enters, rapid depolarization to +20mVDoesn't reach Na+ equilibrium potential bc some V-gated k_ channels are also open TERM 6 Repolarization (3) DEFINITION 6 V-gated Na+ channels close after 1-2 milliseconds K+ channels still open, K+ leaves, membrane potential falls TERM 7 Hyperpolarization (4) DEFINITION 7 Voltage goes below resting bc extra K+ channels are still openNearer to -90 mV (K+ equilibrium potential) than at rest TERM 8 Return to Resting Potential (5) DEFINITION 8 Extra K+ channels close TERM 9 Neural Structure DEFINITION 9 Receive and pass on signals TERM 10 Dendrites DEFINITION 10 Receive neurotransmitters from other neurons Many branchesNo action potential, only graded potentials