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Cardiac Cycle
Steps of Cardiac C chapter 14
Question | Answer |
---|---|
Step 1 Cardiac C | Passive Ventricular filling- Returning venous blood has filled the atria causing their pressure to rise above that in the ventricles. The AV valve open and blood flows into the ventricles. The P wave appears on the ECGs marking the end of atrial depolariz |
Step 2 Cardiac C | Atrial Systole- The AV valves are open and the semilunar valves are closed. The atria contract to eject their remaining volume of blood. The ventricles are relaxed filling with blood |
Step 3 Cardiac C | Isovolumetric Contraction- This is the brief period during which the ventricles are beginning to contract but the semilunar valves havent yet opened. The first heart sound (S1) can be heard |
Step 4 Cardiac C | Ventricular Ejection- When the pressure in the ventricles exceeds the pressure in the pulmonary artery and aorta, the semilunar valves open. Blood spurts out of each ventricle rapidly at first then more flowly as pressure drops. T wave occurs. |
Step 5 Cardiac C | Isovolumetric Ventricular Relaxation- This si the period at the end of the ventricular ejection- before the AV valves have opened but after the semilunar valves have closed to prevent blood from reentering the ventricles. Second heard sound (S2) is heard. |