- Created by: georgiemountford
- Created on: 05-11-19 09:40
- The heart muscle is myogenic - can initiate its own contraction.
- Atrial muscle tends to contract at a higher frequency than the ventricular muscle.
- Fibrillation - Uncoordinated contraction of atria and ventricles.
Initiation and control of the heartbeat
- Sino-atrial node (SAN) at top of right atrium initiates a wave of excitation at regular intervals (pacemaker).
- Wave of excitation spreads over atrial walls and along membranes of muscle tissue, causing cardiac muscle cells to contract - this is an atrial systole.
- The tissue at the base of the atria cannot conduct the wave of excitation, so the wave travels via the atrio-ventricular node (at the top of the interventricular septum), which can conduct the wave through to the ventricles.