Transcript The Heart Continued

The Heart Continued...
• Human heartbeats originate from the SA
node near the right atrium.
• Cardiac muscle cells contract, sending a
signal to other muscle cells in the heart to
contract.
• The signal spreads to trigger the AV node
• Signals carried from the AV node, then
spread and cause the ventricles to contract
simultaneously.
Electrical Conduction
Electrical Conduction
Measurement of Heart
Contractions
• An electrocardiogram (ECG) measures
changes in electrical potential across the
heart
– detects the contraction pulses that pass over the
surface of the heart.
– ECGs are useful in diagnosing heart
abnormalities.
Electrical conduction
across the heart
• The P wave represents the contraction
impulse of the atria, the T wave the
ventricular contraction.
Abnormalities