Primary Viva 6 (Physiology)

1) Draw and compare a pacemaker and ventricular muscle action potential. (Draw each to scale and superimpose them)

– Explain each phase.

– Why are the resting membrane potentials different?

– How are the action potentials affected by:

a) Sympathetic stimulation
b) Lidocaine
c) A beta-blocker
d) A calcium channel blocker
e) Amiodarone

2) What is the Nernst equation?

– Compare the concentrations of ions intra- and extracellularly.

– What is the Gibbs–Donnan effect?
       
3) Draw a graph of CO₂ content versus PaCO₂.

– How is CO₂ carried around the body?

– Explain the Haldane effect.

– Does the graph cut the zero point?

– Draw O₂ content versus PaO₂ on same graph.

– Why does this have a different shape?