Flashcards in 188.8.131.52 control of heart rate Deck (4)
Describe how a heartbeat is initiated and coordinated.
1. SAN sends wave of electrical activity causing atrial contraction.
2. Non-conducting tissue prevents immediate contraction of ventricles / prevents impulses reaching the ventricles;
3. AVN delays (impulse) whilst blood leaves atria / ventricles fill;
4. (AVN) sends wave of electrical activity / impulses down Bundle of His;
5. Causing ventricles to contract from base up;
The sinoatrial node (SAN) is in the right atrium of the heart. Describe the role of the sinoatrial node.
Sends out electrical activity / impulses;
Initiates the heartbeat / acts as a pacemaker / (stimulates) contraction of atria;
When a wave of electrical activity reaches the AVN, there is a short delay before a new wave leaves the AVN. Explain the importance of this short delay.
Allow atria to empty / contract / ventricles to fill;
Before ventricles contract;