Tasks 1-3

After working through the computer simulation program "Frog Heart" you should be able to answer the following questions:

1. Explain why the heart continues to beat after destruction of the spinal cord.

2. Briefly compare the structure of the human heart with that of the frog. Where is the 'pacemaker' located in frog and human hearts?

3. Effects of Adrenaline

1. measure the heart rate before and at 20s after the application of adrenaline.
2. observe any changes in the amplitude (force) of both atrial and ventricular contraction.
3. explain the observed actions of adrenaline and suggest how adrenaline might affect pacemaker activity. At what type of receptor on cardiac muscle cells does adrenaline act. Briefly explain this action.