There is a type of toxin found in the liver of the puffer fish that prevents the opening of voltage-gated Na+ channels in neurons. The effect of this toxin is to: Group of answer choices A. prevents the initiation of the action potential B. depolarizes the membrane potential and maintains it depolarized C. prolongs the return of the membrane potential to the resting level D. increases the duration of the action potential

There is a type of toxin found in the liver of the puffer fish that prevents the opening of voltage-gated Na+ channels in neurons. The effect of this toxin is to: Group of answer choices A. prevents the initiation of the action potential B. depolarizes the membrane potential and maintains it depolarized C. prolongs the return of the membrane potential to the resting level D. increases the duration of the action potential

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

Section4.1: Introduction To Neural Communication

Problem 2CYU

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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?
Draw and label an action potential, indicating the ion movements responsible for the rising phase and the falling phase.
Action potentials occur when ______. a. potassium gates close b. a stimulus pushes membrane potential to threshold c. sodium-potassium pumps become active d. neurotransmitter is reabsorbed
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.
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.
A graded potential that achieves threshold leads to the generation of an action potential. Which one of the following statement/s regarding graded and action potentials is/are true? O graded potentials result from the opening of chemically gated sodium channels O action potentials result from the opening of voltage gated sodium channels O graded potentials result from the opening of calcium gated channels and action potentials result from the opening of sodium gated channels a and b Next
Consider what happens in a segment of membrane during an action potential. In the first column, drag and drop the stages of change in the membrane potential during an action potential. In the second column, match the ion channels related to the membrane stages. A membrane starts at: Resting Membrane Potential lon channels involved voltage-gated potassium channels open Then goes to Depolarization voltage-gated channels closed Then to voltage-gated sodium channels open Then to Resting Repolarization
Which of the following is NOT true regarding the changes that occur during an action potential. Check All That Apply When stimulus is sufficient to cause the threshold potential to be reached, the area stimulated opens its voltage-gated sodium channels.When stimulus is sufficient to cause the threshold potential to be reached, the area stimulated opens its voltage-gated sodium channels. After threshold is reached, the sodium ions move into the cell via the Na+/K+ pump, the inside of the cell becomes momentarily positive.After threshold is reached, the sodium ions move into the cell via the Na+/K+ pump, the inside of the cell becomes momentarily positive. At almost the same time as Na+ channels are closing, voltage-gated potassium channels open, allowing an increased movement of potassium ions out of the cellAt almost the same time as Na+ channels are closing, voltage-gated potassium channels open, allowing an increased movement of potassium ions out of the cell The…
Weaver mice have difficulty maintaining posture and moving normally. This defect has been attributed to a defect in some potassium channels that allows Na+ as well as K+ to pass through the channel. Increasing the sodium permeability will have what effect on the membrane potential of the neuron? The membrane potential will become more negative There will be no change in membrane potential There is not enough information to answer this question The membrane potential will become less negative
Some have compared the "all or none" action potential to flushing a toilet. The relative refractory period (when the water level in the tank is below what it is at rest ) is set by: the opening of the voltage gated sodium channels O the inactivation of voltage gated potassium channels the opening of voltage gated potassium channels the inactivation of voltage gated sodium channels
An 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.
Which of the following does NOT contribute to the establishment or maintenance of the neuron resting membrane potential? Oa sodium and potassium ions are actively transported across the cell membrane which maintains the resting membrane potential Ob. negatively charged proteins are inside the neuron and are not transported out Oc potassium ions are highly concentrated outside the cell and their are many potassium leakage channels in the membrane Od. sodium ions are more highly concentrated outside the cell and there are fewer sodium ion leakage channels in the membrane