Using the figure of an action potential provided, place the following main steps in the generation of an action potential in the correct order starting from the beginning of an action potential. +30- +10- -10- action -30- -50- Threshold -70- -90- 2 Time (msec) 3 a graded depolarization brings an area of an excitable membrane to threshold a temporary hyperpolarization occurs voltage-gated sodium (Na*) channels regain their normal properties sodium ions (Na+) enter the cell and further depolarization occurs voltage-gated sodium (Na*) channel activation occurs voltage-gated potassium (K*) channels fully open and potassium (K*) moves out of the cell, initiating repolarization Membrane potential (mV) > > > >

Using the figure of an action potential provided, place the following main steps in the generation of an action potential in the correct order starting from the beginning of an action potential. +30- +10- -10- action -30- -50- Threshold -70- -90- 2 Time (msec) 3 a graded depolarization brings an area of an excitable membrane to threshold a temporary hyperpolarization occurs voltage-gated sodium (Na) channels regain their normal properties sodium ions (Na+) enter the cell and further depolarization occurs voltage-gated sodium (Na) channel activation occurs voltage-gated potassium (K) channels fully open and potassium (K) moves out of the cell, initiating repolarization Membrane potential (mV) > > > >

Human Physiology: From Cells to Systems (MindTap Course List)

9th Edition

ISBN:9781285866932

Author:Lauralee Sherwood

Publisher:Lauralee Sherwood

Chapter4: Principles Of Neural And Hormonal Communication

Section: Chapter Questions

Problem 17RE

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Similar questions

Draw and label an action potential, indicating the ion movements responsible for the rising phase and the falling phase.
Define an action potential.
Conformational changes in channel proteins brought about by voltage changes are responsible for opening and closing Na+ and K+ gates during the generation of an action potential. (True or false?)
Assume presynaptic excitatory neuron A terminates on a postsynaptic cell near the axon hillock and presynaptic excitatory neuron B terminates on the same postsynaptic cell on a dendrite located on the side of the cell body opposite the axon hillock. Explain why rapid firing of presynaptic neuron A could bring the postsynaptic neuron to threshold through temporal summation, thus initiating an action potential, whereas firing of presynaptic neuron B at the same frequency and the same magnitude of EPSPs may not bring the postsynaptic neuron to threshold.
Figure 35.11 Potassium channel blockers, such as amiodarone and procainamide, which are used to treat abnormal electrical activity in the heart, called cardiac dysrhythmia, impede the movement of K+ through voltage-gated K+ channels. Which part of the action potential would you expect potassium channels to affect?
Match the stages of action potential with the appropriate image or description. 1. Resting membrane potential 2. Threshold 3. Depolarization 4. Repolarization 5. Hyperpolarization 6. Refractory period The potential difference that must be met in order for an action potential to be generated When the potential drops below resting level When the potential starts to decrease again after it has reached a maximum Occurs at -77 mV When the membrane is resetting and an action potential cannot yet be produced again When the sodium channels are open Occurs at -55 mV
The level of depolarization at which an action potential will be triggered is referred to as the Multiple Choice a) cationic potential. b) membrane potential. c) threshold potential. d) refractory potential. e) resting potential.
In an experiment, the extracellular [Na+] surrounding a nerve cell was reduced from 145 to 45 mM. Which of the following is the most likely effect of this on action potentials? No action potentials would occur because the concentration of extracellular Na+ is too low. The membrane potential would become more negative so the threshold for action potential generation could not be reached. The nerve cell would still produce an action potential but its amplitude would be reduced and the depolarisation phase would be slower. The nerve cell would still produce an action potential but its amplitude would be reduced and the depolarization phase would be more rapid.
Describe the events that occur during action potential ANSWER SHOULD INCLUDE: Explanation of how resting membrane potential works and which ions inside/outside Expiation of how depolarisation membrane occurs and which ions move in/how they move in . Explanation of "threshold" . Explanation of depolarisation and which ions move out and how they move out. Explanation of hyperpoarisation and how it is corrected. ( state membrane potential in mv during each stage )
At the peak of an action potential, would the relative permeability of Na be higher than K? Which ion would be the least permeable to the membrane during falling phase?
Draw details of the repolarization phase of an action potential from the following descriptions of the sequences of AfterHyperPolarization (AHP) and AfterDePolarization (ADP) sequences. Make the distinct phases clear and noticeable (5 % each) A complex AHP consisting of a first component AHP, an ADP, and a second component AHP before repolarization to resting membrane potential a first fast AHP component, followed by a slower AHP, followed by a fast ADP, and a second late AHP component before repolarization to rest
Based upon the changes in permeability seen in the trace below and your knowledge of ion distributions across a cell, predict how ion movements would change during an action potential. Drag and drop each phrase into the appropriate box on the action potential trace. Drag the appropriate labels to their respective targets. Note: not all labels will be used. ►View Available Hint(s) Sodium (Na+) ions move to the axon Sodium (Na) ions move out of the axon Less potassium (K) ions move out of the axon Potassium (K) ions move out of the axon Potassium (K¹) ions move into the axon Sodium (Na) ions stop moving in Membrane potential (mv) +30 +10 0 -10- -30 -50 -70 -90 A PNa 0 PNa 5 6 1 PK Threshold PK 2 Reset Help