STARTER: Answer the questions on your handout

Learning outcomes

Everyone shouldDefine action potential, depolarization, repolarization, thresh hold and refractory period

Most will:Outline how an action potential is propagated

Some might:Annotate a graph showing changes in voltage across an axon membrane during action potential

http://outreach.mcb.harvard.edu/animations/actionpotential.swf

Looks complicated?Not if we act it out!!

Pairs activity: Narrate the video

STARTER: Match up the stages to the action

Stage Action

1. Resting potential

• Close Na+ channel• Open K+ channel

2. Depolarization • Ion channel in ‘rest period’• the upstream ion channels cannot open again • only the downstream channels open• action potential moves one-way along the

axon.

3. Repolarization • Na+ pumped out of axon• K+ pumped into axon (but some diffuses out

through K+ channel)• Outside axon is more positive • Inside axon more negative

4. Refractory period

• Membrane potential changes a little (reaches threshold)

• K+ channel closes• Voltage gated Na+ channel opens• Na+ floods into axon• Axon becomes very positive

Learning outcomes

• Define synapse, synaptic cleft, neurotransmitter

• Outline the process of synaptic transmission

Line yourselves up as shown in the diagram belowRemember to leave a space between you to represent the synaptic cleft

What is actually happening?

Another roleplay…why not!!

http://www.blackwellpublishing.com/matthews/actionp.html

INDIVIDUAL ACTIVITY: Try the PPQs!

You have only 10 min!