Cardiac Cycle Flashcards
What is a cardiac cycle
Refers to all events that occur form the beginning of one heart beat to beginning of next
Orderly depo/repo sequence triggers of atrial and ventricular contractions and relaxations
What is Disastole
The heart ventricles relaxed and fill with blood
What is systole
Heart ventricles contract and pump blood into aorta and pulmonary artery
What happens during cardiac cycle
Passive filling Atrial contraction Isovolumetric ventricular contraction Ventricular ejection Isovolumetric ventricular relaxation
What happens in passive filling
Pressure in atria and ventricles close to 0
Av valves open so venous return to ventricles
Aortic pressure 80mmHg
What who one sin atrial contraction
The p wave in ECG signals atrial depo
Atria contracts between p wave and QRS complex
Atrial contraction complete EDV
What is isovolumetric contraction
Ventricular contraction starts after QRS complex in ECG
Vent pressure rises
When vent pressure exceeds atrial pressure the av valves shut producing first sound of closure
Tension rises around isovolumetric contraction
What is ventricular ejection
When ventricular pressure exceeds aorta/pulmonary artery pressure
Aortic valve open
SV ejected by each ventricle leaving behind end systolic volume
Aortic pressure rises
T wave
Ventricles relax and pressure falls
Aortic valve shut second closur sound
What is isovolumetric ventricular relaxation
Closure of aortic signals the start of isovolumetric ventricular relaxation
Vent closed box
Tension falls around closed
Av valves open again and reinto cycle
Hat are the heart sound s
First - caus by closure of mitral and tricuoid valve
Beginning of systole
Second - caused by closure of Aortic and pulmonary valves
Beginning diastole
When does the jugular venous pulse
Jvp occurs after right atrial pressure waves (indirect measurement of central venous pressure)
What happens when heart valves close
Produce a sound
