Lecture 3

Question 1

Spread of electrical excitation through the heart

Answer 1

1. the SA node generates an impulse
2. this impulse spreads through the internodal pathways and into the cardiomyocytes of the atria causing excitation
3. the atria contract
4. the signal is delayed at the AV node
5. after the contraction of the atria is complete the signal travels down the bundle of his and into the Purkinje fibres
6. exciting the cardiomyocytes in the ventricles and causing them to contract

Question 2

ECG

Answer 2

An ECG is a measurement of the electrical differences between cells, measured from the skin by electrodes