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1answer
71 views

Why is pericardium muscle repolarizated earlier than endocardium? [closed]

I was reading about heat muscle contraction and I read: The endocardium depolarization happens earlier than pericardium , but pericarduim repolarization happens earlier, therefore the T wave in ...
3
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1answer
45 views

Why do the size of the phase 1 notch vary among cardiac cells?

The size of the phase 1 notch varies among cardiac cells. It is prominent in myocytes in the epicardial and midmyocardial regions of the left ventricular wall and in ventricular Purkinje fibers. ...
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2answers
64 views

Are Purkinje Action Potentials Neuronal and Cardiac?

I first thought that action potentials of His-bundle i.e. Purkinje fibers are Cardiac. However, I started to think that this is not enough. I think now that they are neuronal and cardiac. My ...
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1answer
28 views

Confusion over role of current/potential in Nervous system?

I am taking a course on the nervous system and I am do not have any physics background. Therefore, I would like to know, what are we precisely talking about when we talk about current in the nervous ...
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1answer
47 views

Does repolarization of muscle fibers mean that the muscle bundle is relaxed?

If I flex my bicep and continue to contract it does it mean that the muscle cells are in depolarizing state and not repolarizing?
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1answer
37 views

Cardiac Excitation Threshold - in C++ modelling [closed]

So I am trying to write a code in C++ about the cardiac excitation threshold. I know that this excitation threshold is the shortest stimulus2 value at which it can conduct an action potential (known ...
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1answer
47 views

All or nothing phenomena

We know that an action potential is produced by an active cell membrane when the stimulus reaches a certain threshold. When it does, an action potential fires, and when it doesn't, nothing happens. ...
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1answer
35 views

What is the mechanism responsible for the 'delay' in delayed rectifier potassium channels?

I've been trying to find a comprehensive explanation concerning the nature of the 'delay' in neurons' delayed rectifier potassium channels. As it's written in my intro to neuroscience textbook, these ...
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2answers
147 views

Can a single axon propagate multiple simultaneous action potentials?

I have not been able to locate any research that indicates whether a single axon of a neuron or nerve cell can conduct multiple simultaneous (i.e. spatially separate) action potentials. I am aware ...
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1answer
52 views

How does core-conductor model correspond to an actual neuron?

Hi guys, looking at your average neuron, it is very difficult for me to imagine how this could be translated into a core-conductor model On the neuron above, where would be the intracellular ...
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0answers
38 views

How to measure Na/K channel activation at the membrane level?

Assume that there are two different signals occurring on the ECG - during depolarization and repolarization in the standard ECG. I was advised not to use the standard ECG in measuring the exact ...
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1answer
135 views

Mechanism of antiperistalsis

What is the mechanism of antiperistalsis that occurs during vomiting? Why the peristaltic waves normally don't propagate in anal to oral direction? Please give logical explanation with authentic ...
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1answer
44 views

Fastest and slowest action potential

When our instructor asked us about the speed of action potentials in cells, I told him that action potentials and two-wheelers travels at similar speeds. He thought that this is an 'interesting' way ...
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0answers
78 views

What is the nature of action potentials in autonomic nervous system?

My conjecture is that the natures of sympathetic and parasympathetic action potentials are different. My findings propose me that sympathetic action potential is little longer lasting than ...
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1answer
43 views

Sodium-Potassium Pump

From my understanding, in the sodium-potassium pump we have Na+ inside the cell and K+ outside the cell, thus forming a so called "salted banana." After reading my textbook I found many statements ...
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1answer
160 views

Refractory period in action potential

I know that the part E in this graph is definitely the part of refractory period. My question : Will there be any effect on B,C or D if a stimulus is given at time B,CorD respectively ?
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1answer
461 views

Action potential and sodium channels

In this video on electro tonic potential, the tutor says that when the potassium channels open the potential drops from +40mV to -80mV, where the sodium channels have already closed at +40mV. Now in ...
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2answers
103 views

Confused at what is happening with these action potentials

Ok so for a bit of a background, I am doing a science project looking at the action potentials of the earthworm. I anaesthatized the worms then hooked them up to a spiker box ...
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1answer
46 views

What happens to potassium after an action potential?

If I understand right, after repolarization, much of the potassium is outside the membrane and much of the sodium / calcium is inside. How does it get back to the original concentrations (i.e. ...
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1answer
1k views

What is the effect of extra-cellular potassium concentration on heart rate and conduction velocity?

If the extracellular potassium concentration surrounding a myocyte increases, then the potassium gradient accross the cell membrane decreases, and therefore the resting membrane potential will become ...
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1answer
136 views

Do nerve cells cause action potential in cardiac muscle?

I think the answer is no, but I am not 100% sure. If it was yes, then the dendrite of the nerve cell should each time receive a stimulus causing Na+ channels to open, when the contraction happen. ...