HUMAN BIOLOGY (LOOSELEAF)
16th Edition
ISBN: 9781260482690
Author: Mader
Publisher: MCG
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Textbook Question
Chapter 14, Problem 5A
Repolarization of an axon during an action potential is produced by
- inward diffusion of Na+.
- outward diffusion of K+
- inward active transport of Na+.
- active extrusion of K+.
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The rising phase of the action potential is due to:
Na+ influx through voltage-gated Na+ channels.
Na+ efflux through voltage-gated Na+ channels.
K+ influx through voltage-gated K+ channels.
K* efflux through voltage-gated K+ channels.
O Na+ influx through Na+ leak channels.
Na efflux through Na+ leak channels.
K+ influx through K+ leak channels.
O K+ efflux through K+ leak channels.
Which of the following is FALSE about action potentials?
At resting potential, there are more potassium channels open and most sodium channels are closed.
Depolarization is due to the flow of Na+ out of the axon via voltage-gated Na+ channels.
Hyperpolarization is due to continued loss of K+ from the axon.
During repolarization, K+ flows out of the axon along its concentration gradient.
Resting membrane potential is primarily established by the Na+/K+ pump.
A membrane potential (Vm) labeled axis on the graph
In the graph draw the phases of the action potential
Include the channels involved and when they open and close matching them to the
Vm
Indicate the periods in which the action potential can or cannot occur
Chapter 14 Solutions
HUMAN BIOLOGY (LOOSELEAF)
Ch. 14.1 - 1.Distinguish between the central nervous system...Ch. 14.1 - Prob. 2LOCh. 14.1 - Prob. 3LOCh. 14.1 - Prob. 4LOCh. 14.1 - What is the likely reason neurons cannot simply be...Ch. 14.1 - Prob. 2BTSCh. 14.1 - Prob. 1CYPCh. 14.1 - Describe how a nerve impulse is propagated.Ch. 14.1 - Summarize how a nerve impulse is transmitted from...Ch. 14.2 - Prob. 1LO
Ch. 14.2 - Prob. 2LOCh. 14.2 - Prob. 3LOCh. 14.2 - Prob. 4LOCh. 14.2 - Prob. 1CYPCh. 14.2 - Prob. 2CYPCh. 14.2 - Prob. 3CYPCh. 14.3 - Prob. 1LOCh. 14.3 - Prob. 2LOCh. 14.3 - Prob. 3LOCh. 14.3 - Prob. 1CYPCh. 14.3 - Prob. 2CYPCh. 14.3 - Prob. 3CYPCh. 14.4 - Prob. 1LOCh. 14.4 - Prob. 2LOCh. 14.4 - Prob. 3LOCh. 14.4 - Prob. 1CYPCh. 14.4 - Prob. 2CYPCh. 14.4 - Prob. 3CYPCh. 14.5 - Prob. 1LOCh. 14.5 - Prob. 2LOCh. 14.5 - Prob. 3LOCh. 14.5 - Prob. 1CYPCh. 14.5 - List how the abuse of drugs, including alcohol and...Ch. 14.5 - Prob. 3CYPCh. 14 - Prob. 1ACh. 14 - Prob. 2ACh. 14 - Prob. 3ACh. 14 - Prob. 4ACh. 14 - Repolarization of an axon during an action...Ch. 14 - Prob. 6ACh. 14 - Which of the following cerebral areas is not...Ch. 14 - Prob. 8ACh. 14 - Prob. 9ACh. 14 - Prob. 10ACh. 14 - Prob. 11ACh. 14 - Prob. 12ACh. 14 - Prob. 13ACh. 14 - Prob. 14ACh. 14 - Prob. 15ACh. 14 - Prob. 16ACh. 14 - Prob. 1TCCh. 14 - Prob. 2TCCh. 14 - Why would you expect the motor skills of a child...
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- 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?)arrow_forwardIn the figure to the left, name the 4 phases of the action potential (Note: you have to write in where phase 4 occurs). Describe what happens in each phase with a focus on Na+ and K+ flow through channels and the membrane potential. Discuss the importance of threshold. How does this relate to the concept of APs being all or none?arrow_forwardThe falling phase of the action potential is due to: Na+ influx through voltage-gated Na+ channels. O Na* efflux through voltage-gated Na* channels. OK* influx through voltage-gated K+ channels. O K+ efflux through voltage-gated K channels. O Nat influx through Na* leak channels. Na efflux through Na+ leak channels. O K+ influx through K+ leak channels. O K+ efflux through K+ leak channels.arrow_forward
- The ion gradient that most neurotransmitters use to be co-transported into nerve terminals is Ca2+ K+ H+ Na+arrow_forwardTable - Summary of the Events of an Action Potential Stage Name of stage Membrane Potential Movement of Na+ or Status of voltage-gated ion channels (mV) K+ in or out of the аxon 1 2 3 4 5arrow_forwardIn 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.arrow_forward
- If a potassium channel is held open for even longer, leading to an even bigger hyperpolarization of the cell what will happen in an afferent neuron? action potentials will have a larger amplitude action potentials will have a small amplitude less frequent action potentials in the neuron more frequent action potentials in the neuronarrow_forwardBased 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 Helparrow_forwardAt 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?arrow_forward
- Dendrotoxins, produced by the mamba snakes (Dendroaspis), are inhibitors of the voltage-gated K+ channels. What phase of the action potential would this toxin affect? How would it affect ion permeability during this phase? How would ion movement be affected?arrow_forwardDescribe the action potential in terms of the different functional states of the voltage- gated Na+ membrane channels (Note: there are three states)arrow_forwardAn action potential is regarded as an example of positive feedback. Which of the following examples below best illustrates the positive feedback aspect of an action potential? Voltage gated potassium ion channels open slowly and remain open long enough to cause hyperpolarization The sodium potassium pump consistently moves ions as long as ATP is available, and regardless of membrane potential changes. A threshold stimulus will cause the opening of voltage gated sodium ion channels that will cause further depolarization by opening still more voltage gated sodium ion channels along the axon.arrow_forward
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