BRAINCAKEContraction of the Heart
The sino-atrial node initiates a wave of excitation which spreads out across both atria. This causes both atria to contract simultaneously.
Non-conducting tissue between the atria and ventricles called the atrio-ventricular septum prevents the wave of excitation spreading to the ventricles.
The excitation wave reaches a group of cells called the atrio-ventricular or AV node in the septum between the two atria.
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Key terms in this lesson
- sino-atrial node
- A small group of cells in the wall of the right atrium that acts as the heart's pacemaker, generating regular electrical impulses that initiate each heartbeat.
More in Neuronal Communication
- Comparison of Neurones
- Receptors in the Eye - Rod Cells
- Receptors in the Eye - Cone Cells
- Sino-Atrial Node
- Autonomic Control of the Heart Rate
- Chemoreceptors
- Pressure Receptors
- Reflex Arc
All 38 lessons in Neuronal Communication · All AQA A-level Biology topics