Human Physiology: An Integrated Approach (8th Edition)
8th Edition
ISBN: 9780134605197
Author: Dee Unglaub Silverthorn
Publisher: PEARSON
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Chapter 8, Problem 18RQ
Summary Introduction
Introduction: The conduction of action potential is initiated by the change in the K+ concentration of blood, which affects the resting membrane potential. The rise in the action potential is due to the increase in the Na+ permeability, and the falling phase occurs due to the increase in the K+ permeability.
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Why does neuronal function require the voltage-gated K+ channels to open moreslowly than the voltage-gated Na+ channels and how would you expect the voltage-gated K+ channels to affect the shape of an action potential curve?
The extracellular sodium [Na+]0 is reduced in the saline bath. Following another current injection
in a neuron, the membrane potential changes were recorded.
a) Why has the membrane potential changed following the Na+ reduction?
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Chapter 8 Solutions
Human Physiology: An Integrated Approach (8th Edition)
Ch. 8.1 - Organize the following terms describing functional...Ch. 8.2 - Where do neurohormone-secreting neurons terminate?Ch. 8.2 - What is the difference between a nerve and a...Ch. 8.2 - Draw a chain of three neurons that synapse on one...Ch. 8.2 - What is the primary function of each of the...Ch. 8.2 - Name the two glial cell types that form myelin....Ch. 8.3 - Given the values in Table 8.2, use the Nernst...Ch. 8.3 - Would a cell with a resting membrane potential of...Ch. 8.3 - Would the cell membrane depolarize or...Ch. 8.3 - Match each ions movement with the type of graded...
Ch. 8.3 - Prob. 11CCCh. 8.3 - What is the difference between conductance and...Ch. 8.3 - If you put ouabain, an inhibitor of the Na+-K+...Ch. 8.3 - The pyrethrin insecticides, derived from...Ch. 8.3 - When Na+ channel gates are resetting, is the...Ch. 8.3 - A stimulating electrode placed halfway down an...Ch. 8.3 - Place the following neurons in order of their...Ch. 8.4 - Prob. 18CCCh. 8.4 - Prob. 19CCCh. 8.4 - Prob. 20CCCh. 8.4 - Prob. 21CCCh. 8.4 - Prob. 22CCCh. 8.4 - Classify the H+-neurotransmitter exchange as...Ch. 8.4 - Prob. 24CCCh. 8.4 - Prob. 25CCCh. 8.4 - Is Na+-dependent neurotransmitter reuptake...Ch. 8.5 - In Figure 8.24e, assume the postsynaptic neuron...Ch. 8.5 - In the graphs of Figure 8.24a, b, why doesnt the...Ch. 8.5 - Prob. 29CCCh. 8.5 - Prob. 30CCCh. 8 - List the three functional classes of neurons, and...Ch. 8 - Somatic motor neurons control __________, and...Ch. 8 - Prob. 3RQCh. 8 - Prob. 4RQCh. 8 - Prob. 5RQCh. 8 - Prob. 6RQCh. 8 - Axonal transport refers to the (a) release of...Ch. 8 - Match the numbers of the appropriate...Ch. 8 - Arrange the following events in the proper...Ch. 8 - List the four major types of ion channels found in...Ch. 8 - Prob. 11RQCh. 8 - An action potential is (circle all correct...Ch. 8 - Choose from the following ions to fill in the...Ch. 8 - What is the myelin sheath?Ch. 8 - List two factors that enhance conduction speed.Ch. 8 - Prob. 16RQCh. 8 - Draw and label a graph of an action potential....Ch. 8 - Prob. 18RQCh. 8 - Prob. 19RQCh. 8 - Create a map showing the organization of the...Ch. 8 - Prob. 21RQCh. 8 - Prob. 22RQCh. 8 - Prob. 23RQCh. 8 - Prob. 24RQCh. 8 - The presence of myelin allows an axon to (choose...Ch. 8 - Define, compare, and contrast the following...Ch. 8 - Prob. 27RQCh. 8 - Prob. 28RQCh. 8 - Prob. 29RQCh. 8 - Prob. 30RQCh. 8 - An unmyelinated axon has a much greater...Ch. 8 - The GHK equation is sometimes abbreviated to...Ch. 8 - In each of the following scenarios, will an action...
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Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, biology and related others by exploring similar questions and additional content below.Similar questions
- 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.arrow_forwardFigure 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?arrow_forwardConformational 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_forward
- 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.arrow_forwardExperimenters injected bark scorpion venom into mouse neurons and measured how many action potentials were generated after the venom was introduced. Is it possible that the venom could be affecting the activity of a voltage-gated potassium channel? What effect could the venom have on a voltage-gated potassium channel to produce this result?arrow_forwardDendrotoxins, 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_forward
- Sequence the following list of events of a neuronal action potential by placing 1 next to the first event, 2 next to the second event, and so on. a. _____ The activation gates of voltage-gated Na+ channels open, Na+ flood the cytoplasm, and depolarization occurs. b. _____ K+ continue to flow out of the axon until the membrane is hyperpolarized. c. _____ Local potentials cause the membrane to depolarize to threshold. d. _____ The inactivation gates of voltage-gated Na+ channels close as voltage-gated K+ channels open, K+ begin to exit the axon, and repolarization begins. e. _____ Repolarization continues and Na+ channels return to restingarrow_forwardNeurons, particularly those in the brain, receive multiple excitatory and inhibitory signals. What is the name of the extension of the neuron at which such signals are received? How does the neuron integrate these signals to determine whether or not to generate an action potential?arrow_forwardWe know the action potential threshold regulates whether a neuron fires an action potential or not. What sets this threshold? Is the action potential threshold the same for all neurons? Why or why not?arrow_forward
- Which of the following is TRUE regarding the absolute and relative refractory periods of the action potential (AP)? A. The absolute refractory period may be overcome if enough excitatory stimulation is applied to the neuronal membrane. B. The absolute refractory period is due the closing of the activation gate of voltage gated sodium channels at the peak of the AP. C. The relative refractory period is due to the closing of the activation gate of voltage gated potassium channels during the overshoot phase of the AP. D. The relative refractory period is due the closing of the inactivation gate of voltage gated sodium channels . E. All of the above statements are FALSE.arrow_forwardWhich are the three different phases of action potential and what characterizes each?arrow_forwardAs the membrane reaches the peak of the action potential, what brings the membrane down to the original resting potential?arrow_forward
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