- In terms of Na and K ion gradient /movement - what causes the action potential (positive charge peak) inside the cell membrane? - What are the approximate Na and K concentration changes (mMoles) during /after the action potential and what is the directional move of each ion in relation to the cell membrane? - What is the duration of an action potential ? or....over what period of time does the peak rise and fall ?-use proper units.

- In terms of Na and K ion gradient /movement - what causes the action potential (positive charge peak) inside the cell membrane? - What are the approximate Na and K concentration changes (mMoles) during /after the action potential and what is the directional move of each ion in relation to the cell membrane? - What is the duration of an action potential ? or....over what period of time does the peak rise and fall ?-use proper units.

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 1RE: Conformational changes in channel proteins brought about by voltage changes are responsible for...

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Similar questions

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?)
Which of the following voltages would most likely be measured during the relative refractory period? +30 mV 0 mV -45 mV -80 mv
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?
Describe the contribution of each of the following to the establishment and maintenance of membrane potential: Part A Na+K+ Pump Passive movement of K+ across the membrane Passive movement of Na+ across the membrane Part B Resting membrane potential is approximately -70mV. Explain what resting membrane potential is and what -70mV refers to.
Draw a typical action potential (correctly label axis) and explain in words the roles of ion channels in generating the different phases of the action potential. (Extra credit: How would opening voltage gated calcium channels upon depolarization affect the shape of the action potential if they have a relatively slow inactivation rate?)
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.
Why is the resting membrane potential a negative value? And how do you determine 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 -20 mV?
At the peak of the action potential, Vm is approximately -65 mV. Assuming normal intracellular and extracellular K+ concentrations (refer to the table), (1) calculate the driving force (in mV) that acts on K+ ions and (2) use the information obtained in part 1 to determine the direction in which K+ ions will flow (i.e., into the cell or out of cell)
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
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
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?