The electrical impulse travels through the following tissues during the cardiac cycle. 1 atrioventricular node 2 muscle wall of atria 3 Purkyne tissue 4 sinoatrial node What sequence does the electrical impulse follow during the cardiac cycle?
- A$1 \rightarrow 2 \rightarrow 3 \rightarrow 4$
- B$1 \rightarrow 4 \rightarrow 2 \rightarrow 3$
- C$4 \rightarrow 2 \rightarrow 1 \rightarrow 3$
- D$4 \rightarrow 2 \rightarrow 3 \rightarrow 1$