Which of the following statements regarding action potentials is false?Na+ channel inactivation is due to a voltage-dependent block of the channel pore.Once Na+ channels enter the inactivated state, the only way to remove the inactivation isby repolarizing them (bring the neuron back to rest).Voltage-gated Na+ and K+ channels begin to open at the same time when the membrane isdepolarized.The probability that voltage-gated Na+ channels will open is increased when themembrane depolarizes.

1. Na+ channel inactivation is due to a voltage-dependent block of the channel pore.This is true.…

Answered: Which of the following statements…

Human Anatomy & Physiology (11th Edition)

11th Edition

ISBN:9780134580999

Author:Elaine N. Marieb, Katja N. Hoehn

Publisher:Elaine N. Marieb, Katja N. Hoehn

Chapter1: The Human Body: An Orientation

Section: Chapter Questions

Problem 1RQ: The correct sequence of levels forming the structural hierarchy is A. (a) organ, organ system,...

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Similar questions

Membrane permeability at the rising phase of an action potential is dominated by: O Co-transporters Nongated Channels O K+ Voltage-gated Channels O Na+ voltage-gated Channels O Chemically-gated Channels
When a neuron reaches threshold voltage, all voltage-gated channels are triggered to make conformational changes. The order in which this happens comes down to the timing/speed/kinetics of the different gates on the channels. Put the following events in the order they occur after a neuron reaches threshold voltage. 1. Voltage-gated K+ channels finish closing their gate. 2. Voltage-gated Na+ channels open their activation gate, increasing Na+ permeability. 3. Voltage-gated Na+ channels close their inactivation gates, reducing Na+ permeability. 4. Voltage-gated K+ channels open their gate, increasing K+ permeability. 5. Voltage-gated Na+ channels reset to their original conformation.
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 neuron
Separately, draw a table using arrows to depict the appropriate magnitude and direction of the forces and ion fluxes at different membrane potentials for a ligand-gated channel that is equally permeable to both ion X+ and ion Y+. The equilibrium potential for ion X+ is -60 mV, and the equilibrium potential for ion Y+ is -20 mV. Which item (a, b, c, or d) best represents the forces and fluxes for a membrane potential of +20 mV? Upwards arrows means outward direction and downwards arrow means inward direction. The length of the arrow determines the magnitude.
An influx of positive sodium ions eventually causes closing of the inactivation gates of voltage regulated sodium channels, stopping the influx of positive sodium ions, and thus the final stages of an action potential are regulated by _____ feedback.
Three currents are produced by a 56 mV depolarization leading to an action potential in a squid axon membrane during a voltage clamp experiment as shown. What is the mechanism underlying the capacitive current? 56 mV Depolarization Capacitative current Late current Early current Time (ms) Opening of Na* channels Current due to the Na/K* pump O Neutralization of the charge on the membrane Opening of K channels Membrane Membeane current imA/cm potential (mV)
Which of the following situations in a neuron results in action potentials that have extended depolarization phases? O None of these result in extended depolarization phase. O Compromising the inactivation mechanism in voltage-gated Na* channels. O Stimulating the voltage-gated K* channels. O Inhibiting the voltage-gated Na* channels. O Compromising the inactivation mechanism in voltage-gated K* channels.
Describe the events of an action potential in terms of ions and gates or channels beginning with the generation of a local potential through the re-establishment of resting membrane potential.
Separately, draw a table using arrows to depict the appropriate magnitude and direction of the forces and ion fluxes at different membrane potentials for a ligand-gated channel that is equally permeable to both ion X+ and ion Y+. The equilibrium potential for ion X+ is -60 mV, and the equilibrium potential for ion Y+ is -20 mV. Which item best represents the forces and fluxes for a membrane potential of -40 mV (a, b, c, or d)? Upwards arrows means outward direction and downwards arrow means inward direction. The length of the arrow determines the magnitude.
rearrange these in the correct order of events in an action potential.
Place the following events in chronological order from 1-8: Nat enters the cell, and depolarization occurs to approximately +30 mV. The voltage across the cell membrane is -70 mV, the resting membrane potential. Upon reaching the peak of the action potential, the VG Nat channels are inactivated by the closing of their inactivation gate and the activation gate of each VG K channel opens. VG K channels close by the closing of their activation gate, and the resting membrane potential is gradually restored. An excitatory post-synaptic potential depolarizes the membrane to threshold and the activation gate of VG Nat channels open. Upon returning to the resting membrane potential, VG Na channels are reset by opening of the inactivation gate and the closing of the activation gate. VG K+ channels are slow to close, resulting in an excess of K* efflux and hyperpolarization. Depolarization occurs as K+ flows out of the cell.
An action potential Membrane potential (mV) -40 40 -65 II -80 0 -Overshoot Rising Falling phase phase III Voltage threshold Resting potential Undershoot 1 2 3 4 Time (ms) In the figure above, which arrow best represents the point where the voltage-gated sodium channels are inactivated and locked? OI ○ III O IV ○ II

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