BIOL 320 Lecture Notes - Lecture 6: Heart Valve, Purkinje Fibers, Cardiac Action Potential
14 Jan 2017
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The pattern of electrical activity recorded at the body surface. Oxygenated blood arrives at left side of heart. Contractions do not rely on nerve supply. Yes, sinus arrhythmia, respiratory affects heart rate. Through the muscle fibers of the atria. Contractions that push blood into the ventricles. The only electrical connection between the atria and the ventricles. Describe the characteristics of the action potential: Spreads slowly through av node, to allow atrial contraction to contribute to ventricular filling. Then spreads rapidly through av bundle and purkinje fibers to excite both ventricles. A sequential contraction of atria and the ventricles. Combined electrical activity of different myocardial cells. Currents are large enough to be detected by recording electrodes placed on skin. Ensures the atria have ejected their blood into the ventricles before the ventricles contract. When these valves open, blood flows into the arterial system: When blood enters arteries through semilunar valves, they become stretched out.
