Re: pinhole Nervous system and voltage

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From: Paul Doherty (pauld@exploratorium.edu)
Date: Sat Nov 17 2001 - 09:24:05 PST 

Message-Id: <l03110701b81c4c8abec4@[192.174.2.173]>
Date: Sat, 17 Nov 2001 09:24:05 -0800
From: Paul Doherty <pauld@exploratorium.edu>
Subject: Re: pinhole Nervous system and voltage

Hi Jhumki

There are ion pumps in the membrane of the nerve cells. These pumps move
sodium, potassium and calcium ions. Negative ions and electrons are not
directly pumped but move due to electrical forces from the charge imablance.

The ion pumps are batteries.

They create a charge difference bertween the inside of the nerve cell and
the outside. This charge difference gives rise to a volatge difference. The
inside and outside of the cell are conductors, the cell membrane is an
insulator. So the membrane acts as a capacitor. The conductor inside the
cell has resistance and so acts as a resistor. However a volatge difference
across one part of a nerve cell triggers the neighboring parts ion pumps to
turn on. Chemical energy is turned into electrical energy. This is the
equivalent of an electronic amplifier.

Paul D

Paul "But it is more complicated than that!" Doherty,
Senior Staff Scientist, The Exploratorium.
pauld@exploratorium.edu, www.exo.net/~pauld

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