BRAINCAKEControl of the Heartbeat
Cardiac muscle is myogenic, but the heartbeat still needs to be coordinated so that the atria contract before the ventricles. This is done by specialised tissue in the heart that generates and conducts waves of electrical excitation.
1. Sinoatrial node (SAN). The SAN is a small patch of tissue in the wall of the right atrium. It acts as the pacemaker, generating a wave of electrical excitation at regular intervals.
2. Spread across the atria. The wave spreads across the walls of both atria, causing them to contract (atrial systole).
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More in The Heart
- Structure of the Human Heart
- Blood Flow through the Heart
- Contraction of Cardiac Muscle
- The Cardiac Cycle
- Electrocardiograms
- Electrical and Pressure Changes in the Heart
All 7 lessons in The Heart · All Edexcel AS-level Biology topics