Answered: Which of the following intracellular…

Which of the following intracellular potentials would have the greatest electrical attraction for Na+ to enter the cell? -70mV -100mV -50mV OmV +20mV

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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Epilepsy is a condition which results in seizures stemming from excessive or abnormal activity of neurons. This can occur either from hyperexcitability of excitatory neurons, or impairment of inhibitory neurons. That is to say, either the excitatory pathways become overactive, or the inhibitory pathways, designed to temper the excitatory pathways, are not active enough. Much of the research done on epilepsy focuses on voltage-gated sodium channels, and to date over 700 different mutations to the channel have been identified as playing a role in epilepsy. The means by which these mutations contribute to epilepsy is quite complex, but for the sake of this CAL, let's simplify and apply what we have learned so far to identify potential mechanisms for this condition. In what way could voltage-gated sodium channels be affected in excitatory neurons which would increase the likelihood of the neuron firing an action potential? (one correct answer) The inactivation gate is slower to close. The…
Which of these ions is actively transported through the cell membrane to re-establish a resting potential? K and Mg Na and K Mg and Cl Ca and Cl
If the resting membrane potential of a cell was +70 mV, the ELECTRICAL driving force on sodium would be: Group of answer choices into the neuron out of the neuron balanced
A True OUTSIDE CELL This cell is at rest. False INSIDE CELL C D T E
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.
Based on this chart, which way will sodium be pumped? Typical ionic concentrations Squid Giant Axon Frog Sartorius Muscle Intracellular Na+ K+ CI- Extracellular Na+ K+ CI- sodium is a equilibrium into the cell out of the cell 50 397 40 437 20 556 sodium cannot cross the membrane 13 138 3 110 2.5 90 Human Red Blood Cell 19 136 78 155 5 112
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
State whether the channels listed would be open or closed at the corresponding numbered phases of the action potential graph. Phase on Graph Sodium Voltage Gated channels Potassium Voltage Gated channels 1 2 3 4
During the action potential waveform, the voltage returns to the resting membrane potential at -70mV through the: closing of potassium channels. opening of chloride channels. O opening of sodium channels. opening of potassium channels.
A resting cell's membrane is more permeable to K+ simply because: K has a higher atomic number than Na. The Na+/K+ ATPase only works in response to a stimulus. There are more voltage-gated K+ channels than voltage-gated Na+ channels in the cell membrane. There are more K+ leaky channels than Na+ leaky channels in the cell membrane.
Fill in the diagram, your illustration should demonstrate for each phase of the AP: 1. The relative concentration of K and Na 2. The relative voltage across the membrane 3. Any movement across the membrane of K and NA 4. The three kinds of channels in the membrane, and their state (open or closed) 5. Finally, indicate on the graph of the AP which phases correspond to hyper- polarization and which phases correspond to de- polarization Outside Outside Inside Inside Outside Inside Outside 1 Outside Inside Inside
dendrotoxins, produced by the mamba snakes are inhibitors of the voltage gated k+ channel. what phase of the action potential with this toxin effect? how would it affect ion permeability during this phase howard ion movement be affected?