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Depolarization

Definition

noun

The deprivation or the process of neutralization of polarity, as that in nerve cells


Supplement

Depolarization is the process or the act by which polarity is eliminated. It may also refer to the result of such action so that the result is an unpolarized condition. In physiology, depolarization occurs in a living cell (e.g. nerve cells). Depolarization in a nerve cell occurs when the cell undergoes an electrical change. Most cells are negatively charged relative to their surroundings. This negative internal charge of the cell shifts to a positive through the process of depolarization. Depolarization though occurs for only a brief period of time.

Depolarization is essential because it allows the transmission of electrical signals (impulses) within the cell, and in certain instances, from one cell to another. Depolarization therefore is one mechanism employed by cell to carry on certain physiological functions and also to communicate with another cell.


Word origin: Latin (from, away from, out of) + polarization

Variant(s):

  • depolarisation

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Re: Depolarization = ion channel opening?

I think you are correct (or more precisely when the Na+ channels open since the K+ open later). There is a threshold voltage that switches the state of what I found to be a flip-flop. The circuit is also called a "monostable multivibrator".

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by GaryGaulin
Thu Jan 08, 2015 6:01 am
 
Forum: Cell Biology
Topic: Depolarization = ion channel opening?
Replies: 1
Views: 671

Depolarization = ion channel opening?

Hi huys, I have a problem with this statement: "Action potentials are formed when a stimulus causes the cell membrane to depolarize past the threshold of excitation, causing all sodium ion channels to open." Isn't the cell membrane depolarized BECAUSE the ion channels open?

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by autumnsphere
Wed Oct 29, 2014 2:18 pm
 
Forum: Cell Biology
Topic: Depolarization = ion channel opening?
Replies: 1
Views: 671

How can depolarization activate VGCC and TRPM5

Hi, I know that depolarization of a cell --> activates VGCC --> Ca2+ increases --> opens TRPM5 channels to let more Ca2+ in. But my questions are: 1. What is the mechanism behind the activation of VGCC? 2. How can TRPM5 channels ...

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by Jessiyoo
Wed Jul 31, 2013 4:45 pm
 
Forum: Molecular Biology
Topic: How can depolarization activate VGCC and TRPM5
Replies: 0
Views: 853

[NEUROSCIENCE]-Two Questions about AP Propagation

... Attempt: a stimulus causes the activation of special ion channels (not the voltage-gated ones) that cause ions that go into the cell which induce depolarization (for instance: the Na+ ion influx). Given that the influx via these special channels reaches threshold, THEN the Na-VG channels open, ...

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by AbducensNucleus
Sun Aug 05, 2012 4:19 am
 
Forum: Human Biology
Topic: [NEUROSCIENCE]-Two Questions about AP Propagation
Replies: 5
Views: 6297

Impulse propagation/local circuits and repolarisation

first sodium flows inside and cause depolarization (because the membrane is already polarized) then the potassium gets outside and causes repolarization (the action potential gets back to starting value) during resting the concentrations of ...

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by JackBean
Tue Jan 31, 2012 3:04 pm
 
Forum: Human Biology
Topic: Impulse propagation/local circuits and repolarisation
Replies: 1
Views: 1567
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