Questions tagged [electrophysiology]
The study of the electrical properties of biological cells and tissues.
164
questions
0
votes
0answers
23 views
Simulating a circuit diagram for action potential [migrated]
Cable theory is a good simulation for the resting potential. It imagines patches of cell membrane lipid bilayer as capacitors and transmembrane ion channels as resistors.
But it seems this model is ...
0
votes
0answers
17 views
If electrical muscle stimulation activates muscles the same way a brain does, why doesn't it result in the same muscle mass increase?
I've been reading about Electrical muscle stimulation (EMS), (also known as neuromuscular electrical stimulation or electromyostimulation).
All resources stress that the electrical signals used by EMS ...
0
votes
0answers
28 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 ...
1
vote
1answer
53 views
GHK Equation and Action potential
Can GHK equation be used to predict the membrane potential even if the cell is not at resting state?
To say it again, can we use GHK equation at every moment during Action potential?
I'm confused ...
-1
votes
1answer
33 views
Using Nerve Conduction Studies to determine nerve regeneration
I was reading a paper investigating using MRI as a way to determine peripheral nerve regeneration: https://sci-hub.do/10.1016/j.expneurol.2009.10.012
They mention that
... nerve conduction studies ...
1
vote
0answers
19 views
Potential obstacles to growing nanoelectronics within living cells? [closed]
Say there was a nanotechnology allowing to "grow" and wire up electronic components/sensors measured only a few nanometers in cross-section, though spanning in length across microns. Say ...
2
votes
0answers
25 views
Can high energy photoelectrons damage cell membranes?
I've read that in addition to ionizing radiation causing damage to DNA through direct absorption, but DNA can also be damaged through photoelectrons with enough energy. The thing I was wondering is ...
2
votes
2answers
159 views
How many Watt-hours can an electric eel produce in a day?
Electric eels are cited as being about to produce about 860 watts of energy. But I haven't been able to find information on how long they can sustain their charge.
https://www.youtube.com/watch?v=...
4
votes
1answer
113 views
Do electric eels produce current as they just move about, and how/why?
https://www.youtube.com/watch?v=y9wktSQdyaE
This video demonstrates how an electric eel can supposedly produce up to 800 watts, and power a Christmas tree, which is very topical (a late Merry ...
2
votes
0answers
58 views
How can I simulate heart electrical activity in a 2D plane?
I am not a biologist/medical student, I study software engineering. But I really like when medicine and engineering hold their hands together to achieve great things.
As a side/toy project, I was ...
0
votes
1answer
40 views
What is a "membrane holding potential"?
What is a membrane holding potential? I have come across this term but haven't been able to find a definition.
From "Voltage-gated sodium channels as therapeutic targets in epilepsy and other ...
1
vote
0answers
19 views
Is there a way to derive Bazett's formula to correct QT interval in ECG?
As we know that QT interval in ECG is a function of heart rate (HR) and to comment on the pathology associated with altered QT interval, we must neutralise the effect of HR. For this Bazett's formula ...
0
votes
0answers
21 views
How do I stimulate a neuron extracellularly, specifically the sphenopalatine ganglion
Apologies if this is too basic of a question, but I am an electrical engineer, just getting into neuromodulation/neurostimulation.
For my senior project, I am trying to make a device that stimulates ...
-1
votes
1answer
36 views
What's a cells membrane potential without any leak channels?
Consider the following ion concentrations on either side of a cell membrane (in = inside cell, out = outside cell):
$[\text{Na}^+]_{\text{in}} = 10mM$,
$[\text{Na}^+]_{\text{out}} = 142mM$,
$[\text{K}^...
1
vote
1answer
108 views
Why is the current flow shown to be flowing from the negative area towards the positive area?
When I was studying the ECG chapter in the book "Guyton and Hall Textbook of Medical Physiology", I noticed something odd in one of the pictures:
As you can see the current is shown to be ...
2
votes
1answer
99 views
Why does increasing the space constant increase conduction velocity in myelinated neurons if nodes of Ranvier are constantly spaced?
If depolarisation at one node of Ranvier triggers, by passive conduction, an action potential at the next node of Ranvier, why does increasing the space constant increase conduction velocity? Surely ...
1
vote
2answers
209 views
At small axon diameters (<1 µm), why does myelination not increase neuronal conduction velocity?
As per the diagram below (and other graphs available online), why do unmyelinated fibres have a higher conduction velocity than myelinated fibres when the axon diameter is less than around 1 µm?
0
votes
0answers
34 views
Effect of opposing electric charges on cells
Is the affect on a cell between two negatively charged plates theoretically similar to between a positively and negatively charged plate? In other words, would it induce charges on the inside and ...
0
votes
0answers
53 views
Is there a proton gradient across the cell membrane, just like for the mitochondrial membrane?
Mitochondria have a proton gradient, is there also a proton gradient between cells and the extracellular medium?
3
votes
1answer
136 views
What is the significance of the amplitude of brain waves?
What does the amplitude of brain waves represent and to what neuronal activities is this amplitude related to?
For example, in a hypothetical situation, the frequency of brain waves is kept the same, ...
1
vote
1answer
25 views
Question about the Derivation of the cable equation for neurites
I read in Wikipedia how the cable equation was derived (here) and had a specific problem regarding one of its equation:
At the start of the derivation it states that we first need to pretend that the ...
1
vote
1answer
46 views
Why the length constant of passive current flow isn't depend on the membrane capacitance?
I read that the equation for the length constant for passive conductance along a neuron depend on the resistance of the plasma membrane, the intracellular axoplasm and the extracellular medium. My ...
2
votes
1answer
87 views
Help me understand voltage patch clamping
Before I type my question it is important to know that I already tried looking this up on my own and could not find an answer because the answers are all in complicated physics terms and this topic is ...
4
votes
1answer
151 views
electrostatic charge of viruses, especially Coronaviruses
I am searching for (and failing to find) literature about the electric charge (+/-) of viruses, specifically the Coronaviruses. I am aware that it is a complicated issue, including interaction of pH ...
1
vote
1answer
48 views
What is happening at the electrode interface when the electrical field is modified due to the change of ion concentration after an AP?
I have been working for quite a while now on electrophysiology and electrode fabrication.
I studied what is happening at the neuron level during an action potential (polarization/depolarization, ...
0
votes
0answers
27 views
Does the zeta potential of a nanoparticle generally take into account ligand charge?
For example, if I had a quantum dot nanoparticle with conjugated linker peptides capped with polyarginine tracts.
Would the localization of negative charge from arginine change the zeta potential ...
1
vote
1answer
74 views
In the PR segment of an ECG, how come there's no current flowing?
I don't really know how to phrase the question, but to put it as clearly as I can, I don't get why it is the P wave "flattens down" when the atria have completely depolarized. I get that the ...
1
vote
1answer
58 views
Physiology of hyperpolarization
In my textbook, it is stated that after the closure of potassium voltage-gated channels and during hyperpolarization, potassium leakage channels allow potassium influx passively and this returns the ...
1
vote
1answer
2k views
Difference between Premature Atrial Contraction and Atrial Fibrillation
what is the difference between Premature Atrial Contraction and Atrial Fibrillation. I know that both have irregular heart beat but have normal QRS complex. Both have abnormal or absence P waves but a ...
2
votes
1answer
42 views
Definition for different arrhythmia
I am wondering if there is an organization, a document or a research that standardize all the rhythms? Such as describing how long should the ECG be flatline to be considered as asystole? The rhythm I ...
6
votes
1answer
125 views
Where does this equation in the electrophysiology literature form come from?
In my studies I keep coming across the form of an equation that is used in many different mathematical models for voltage gated ion channels. The most general form I have found is in the 1977 paper ...
1
vote
0answers
31 views
Is the medium which transmits the electrical impulse through the heart different to a nerve?
According to Nerve
A nerve is an enclosed, cable-like bundle of nerve fibres called axons
Being an Axon
An axon (from Greek ἄξων áxōn, axis), or nerve fiber, is a long, slender projection of a ...
6
votes
1answer
630 views
Why do larger diameter myelinated axons have greater conduction velocities than small diameter myelinated axons?
A canonical statement I have frequently read is that "large diameter axons conduct action potentials at faster velocities than small diameter axons". After recently learning the effect of increased ...
1
vote
0answers
67 views
Are large cell bodies of neurons harder to depolarize than small cell bodies of neurons?
In order for the axon to initiate an action potential, we know that the axon initial segment must be brought to threshold. So my question is as follows:
Say we have the minimum charge input, "X", ...
1
vote
0answers
97 views
What is the difference in the electrical excitability between a "large diameter soma" and a "large diameter axon"
There are two stereotyped statements that I have seen during my coursework regarding electric properties of neurons:
Large diameter axons propagate action potentials more quickly than small diameter ...
5
votes
1answer
81 views
At What Rate Do Ions Leak Out of a Plasma Membrane Segment That Has No Ion Channels?
In reading about the purpose of myelin during action potential propagation, I came across a point of confusion.
From what I understand, one of the primary "benefits" of myelin is that it aids in ...
1
vote
1answer
185 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 ...
1
vote
0answers
30 views
What causes bio electricity? [closed]
When it is said that “electrical impulses sent from the brain” how is this charge flow produced?
3
votes
0answers
152 views
Living potato clock? [duplicate]
Could a potato stay alive and power a clock while growing in the ground?
I know how a potato clock works as a electrochemical cell and involves chemistry, but I am only interested in a growing ...
1
vote
1answer
41 views
Entropy during neuronal signaling
to begin with: I have some background in cognitive neuroscience, but have not intensely studied the biochemical background of neuronal signalling, so please correct me if my basic understanding is ...
4
votes
0answers
38 views
How do scientists determine the nature of ions passing through a channel/carrier/pump?
The NCE (Sodium Calcium Exchanger) transports 3 Na+ inside the cell for 1 Ca2+ outside.
How did we figure this out, and other mechanisms of this sort?
If it were a protein, we could tag it with GFP. ...
6
votes
2answers
165 views
Are there any organisms, extant or extinct, that have only one neuron?
Nervous systems are useful in one way because they allow for integration of complex information. They are also useful because they transmit information very rapidly, over a large distance.
However, ...
0
votes
0answers
67 views
Action potential frequency presynaptic neuron comared with in post-synaptic neuron/ muscle cells
I am a physicist interested in knowing how the action potential frequency in a presynaptic neuron compares with that in
a) a post-synaptic neuron and
b) membrane depolarisation of muslce cells, ...
5
votes
2answers
105 views
How is the electrical potential difference distributed between two stimulating electrodes?
Suppose I set the voltage value of an isolated stimulator with a floating ground. I place one electrode above the spinal cord (positive) and the other placed subcutaneously far away from the spinal ...
3
votes
2answers
350 views
What is the maximum electric potential that can occur in the human body?
Neurons can generate a voltage, if there is an action potential. Also, membranes where an ion concentration gradient is present, generate some membrane potential.
What I wish to know is, which ...
0
votes
1answer
40 views
What is (are) the medium of conduction for an electrical current with an external source in the human body?
I am trying to get some background for some personal research I am doing into the effects of Electro Convulsive Therapy. I don't understand how electric current from an external household source, say, ...
2
votes
0answers
45 views
Is it possible to create a biological radio? [closed]
If someone had taken the genome for a basic single or multi-celled organism, and had the understanding of genetic code to write his own program, is it possible on a fundamental level to create the ...
1
vote
1answer
399 views
What is (roughly) the net charge of the DNA in an average human cell?
I was wondering about what general range for the net charge of DNA in human cells is in Coulombs. I imagine that kind of thing would be hard to measure but could be approximately calculated/estimated....
3
votes
1answer
241 views
Is the ACh receptor more permeable to sodium ions?
The AChR is permeable to sodium and potassium ions only and has a reversal potential of 0mV.
However the Nernst potentials for sodium and potassium ions is ~ +60mV and -88mV respectively. Taking a ...
3
votes
1answer
79 views
The information carried by nerve signals
Action potentials carry nerve signals in individual neurons and somehow encode information. My question is if it is possible to read that information carried by the nerve signal and feed it into a ...
Hot Network Questions
- How much of Twister is true?
- Bang sound and breaker has tripped, anything else to check?
- What could be causing my dog to constantly lick her paws?
- Remove words from a string that contain special characters
- Why use random characters in passwords?
- 'We Americans like baseball' or 'Us Americans...'?
- Why would it be drier indoors during the winter vs the summer?
- How to upgrade from Yosemite to Monterey?
- Bash Regex pattern for password to exclude specific special characters with negative lookahead
- Shortest term as prime minister?
- Reading in external single cell data
- Explain in layperson's terms why predictive models aren't causally interpretable
- LTspice diode bridge rectifier output oscillating
- Timing attacks: Symmetric vs Asymmetric Algorithms
- Should I assume data passed to my function is accurate?
- Why does my dd Full Disk Copy Keep failing at 8 GB?
- What magic items would best make a (corrupt) city guard competitive with Paragon tier heroes?
- Can you identify this LEGO part? - 8x8 lattice design with 2 studs by 2 studs in the middle
- Is it possible to make a vaccine against cancer?
- Math PhD program admissions: what happens between December and February?
- What would be a realistic length of minimal compulsory military service for a modern country's occupants?
- Did commercial air planes in 1972 really not have some sort of automatic distress call equipment?
- What is the record word size for a gaming system?
- How to choose capacitor voltage rating for ESD protection?