On 04-17-92 ALLEN SMITH wrote:
AS>Strictly speaking, repolarisation time is the time it takes for the
AS>membrane potential to return to rest from the peak of the depolarising
AS>phase of the action potential. This is generally less than 1ms in
AS>normal neurones. Following repolarisation, there is a period called
AS>the refractory period during which it is impossible/difficult to evoke
AS>subsequent action potentials. The length of this period is very
AS>variable from neuron type to neuron type and can be hundred of ms
AS>long, or only a few tens... 'it depends'.
AS
AS There seems to be a contradiction in the definitions of refractory
ASperiod and repolarization time. What's the name for how long it takes
ASbefore a neuron can send a signal again?
That's what he said -- refractory period is how long it takes
before a neuron can send a signal again, "the...period during
which it is impossible/difficult to evoke su=bsequent action
potentials." (Action potential = propagation of signal). In
essence, repolarization time is a mechanically defined term,
refractory period a functionally defined one. I think it's
invariably true that refractoriness is resolved by a *tendency*
toward repolarization, but not necessarily return to baseline.
That's the difference.
012 eliot 210
Internet: eliot.gelwan at channel1.com
RIME: ->CHANNEL [R/O okay]
---
~ EZ 1.37B #178 ~ [in Brookline MA 10:02 am, Friday 04/17/92]
--
Channel 1 (R) Cambridge, MA
