Linked Questions
0
votes
0
answers
29
views
How Fast can the Electrochemical Gradient on a Neuron be Reestablished? [duplicate]
The electrochemical gradient of Na+, K+, Ca2+, and Cl- between the inside and outside of a neuron is vital for its function. When a neuron fires, this gradient reverses. How long does it take for the ...
- 956
11
votes
1
answer
921
views
Purpose of K+ channels in action potential
I understand that they serve to repolarize the neuron after the Na+ influx. What I don't understand is why this is important.
Meaning, let's say all the K+ channels disappeared. So now the ...
- 337
4
votes
2
answers
4k
views
Sodium concentration during action potential generation
At the peak of the graph, is the concentration of Na+ outside the cell more than inside? That must be to overcome the electrical force in the opposite direction.
When is the concentration of Na+ ...
- 41
1
vote
1
answer
2k
views
How greater magnitude implies greater frequency of action potential?
Greater the magnitude of receptor potential, greater is the rate of discharge of action potentials in the nerve fibre.1
Now consider a case where stimulus ( strength ) is large , so there is more ...
- 4,836
2
votes
2
answers
2k
views
Why is the resting membrane potential of excitable tissue not affected by the extracellular sodium concentration?
I know that the resting membrane potential for excitable tissue (eg, nerve) is primarily determined by the electronegative difference between the inside and the outside of the membrane for potassium ...
- 43
6
votes
1
answer
539
views
What Produces the Postive Potenial in the lumen of the thick ascending loop of Henle?
In the Thick Ascending Loop of Henle, Paracellular diffusion of certain Solutes like magnesium and calcium takes place. Such diffusion is a result of the positive lumen potential.
Looking at the image ...
4
votes
1
answer
662
views
Are living cells electrically neutral?
I found random scientific table which had a comment attached:
the cells must be electrically neutral.
Per my knowledge whole intracellular solution contains more electrons than protons (definition ...
4
votes
1
answer
1k
views
How does a neuron recover from after hyperpolarization?
My question is, how does a neuron recover from AHP? It’s been puzzling me for a long time, and I really can’t find a single source that explains it in detail. Apparently the sodium potassium pump ...
- 41
2
votes
2
answers
966
views
Ambiguity about the relation between membrane potential and concentration gradient in neuron cells
I am stuck in an ambiguity about the equilibrium potentials of neuron cells. The following text is picked up from khanacademy website:
In one part it is said that:
We'll start out with K at a higher ...
- 121
1
vote
1
answer
397
views
Assumptions for Nernst Equation
While I am familiar with some of the conditions for the Nernst Equation, for example:
1) "The membrane is only permeable to one ion even if there are several other ions in the system"
there is an ...
- 393
0
votes
1
answer
174
views
How is Na concentration re-established after action potential
I understand that the repolarization is because some K+ chanels are opened with the action potential. But whats happens with the sodium chemical gradient that is needed for a new action potential? Are ...
3
votes
1
answer
192
views
What is the basis of the endocochlear potential?
I am learning about the endocochlear potential. According to different sources, the ionic composition of perilymph is about as follows (in mM): 150 Na+, 4-5 K+, 1.2 Ca2+, 1 Mg2+, 120 Cl−, and 20 HCO3−;...
- 31
1
vote
1
answer
354
views
Why don't membrane potentials violate the principle of electroneutrality?
The principle of electroneutrality states that the number of anions and cations in a solution must be the same, i.e., that there will be no charge excess in any side of the membrane separating two ...
- 61
2
votes
1
answer
200
views
Nernst Equation and Membrane Potential
I am a bit confused on how to use the Nernst equation to determine polarization.
I saw in the textbook that if potassium channels were open in a neuron cell, there will be a net diffusion of $\ce{K+}$ ...
- 59
2
votes
1
answer
139
views
Chloride Clamp and Nernst potential
The Nernst potential for chloride is -70 mV. The neuronal Resting Membrane Potential (RMP) is -70 mV. Under this condition, if the chloride channels are open (as it happens in Inhibitory Post Synaptic ...
- 3,082
3
votes
0
answers
78
views
Movement of few ion during changes in membrane potential
My question is very simple: why is it sufficient for a very few ions (such as 1 in 100000 K+) to move across the membrane to generate a remarkable variation in the membrane potential (like a change of ...
- 31
0
votes
0
answers
60
views
Na+ / K+ ATPase: How does it restore resting membrane potential? [duplicate]
Could not find any sources talking about this (in a clear manner). If the Na+ / K+ ATPase pumps 3 Na+ out for every 2 K+ it pumps in, thus making the cell more negative, why is the Na+ / K+ ATPase ...
- 329
0
votes
0
answers
32
views
Doubt related to nerve impulse transmission
Naturally, the extracellular fluid has more sodium ions and the axoplasm has more potassium ions. Since there are more potassium leakage channels than sodium leakage channels on axoplasm, it is more ...
0
votes
0
answers
20
views
Why does increasing concentration of extracellular sodium have no effect on electrical gradient of potassium? [duplicate]
I learnt that the permeability of an ion across the membrane contributes to the membrane potential as much as(or even more than) its concentration and electrical gradients. And so far I've made peace ...
- 143