3.2.9 Heart Action: Initiation & Control Flashcards
1
Q
Heat initiation
A
- SAN (top right of right atrium) initiates wave of excitation
- Spreads over walls of atria
- Atrial systole
- Wave of excitation reaches atrioventricular node
- Delay is caused so atria has time to finish contracting and pushing all the blood into ventricles
- After delay, wave of excitation passes down from AVN to Bundle of his (purkyne tissue) running down interventricular septum
- Reaches base then spreads upwards and out over walls of ventricle
- Depolarisation of ventricles occurs
- Ventricular systole
