Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2010 Ludek Nerad Introduction...

transcript

Introduction To Action Introduction To Action PotentialPotential

PhysiologyPhysiologypage 1page 1

Content

Terminology

What action potential really means

Where we can find it

Neurones

Networks of neurones

Processing of information

A temporary reversal in the potential difference across a plasma membrane that occurs when a cell has been activated by a stimulus.

Action potential definition

Potential energy = potential to deliver work

U = m x g x h

Tsunami

U = Q1 x Q2 / r

= 1.5 V

~ 220 V

U … voltage

Q1 … charge

Q2 … charge

r … distance

Electric potentialis a voltage thatwe measure witha voltmeter.

Electric currentis a movement offree electrons.

Ions exert forceon free electronswhich move thevoltmeter pointer.

Where can we see action potential?

NeuronesPacemakercells

Neuromuscular junction

Action potentialAction potential

Conduction in myelinated vs. non-myel. neurones

10 – 120 m/s10 – 120 m/s

5 - 25 m/s5 - 25 m/s

Saltatory conduction

5 m5 m18 m18 m

Synaptic transmission

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