The dive phases of the cardiac cycle Flashcards
the isovolumetric phase of the systole
Which phase?
phase 3
the ejection phase of the ventricular system
Which phase?
Phase 4
Phase 1 describes what, and what happens?
The heart at rest: atrial and ventricular diastole
The atria are filling with blood from the vein
AV valves open ventricles fill
(passive filling)
Phase 2what occurs and how?
Completion of ventricular filling: atrial systole
-Atria contract
- Last 20% of blood volume driven to ventricles
- End-diastolic volume (EDV): volume in ventricle at the end of ventricular relaxation
Last 20% of blood volume driven to ventricles
phase 2
EDV established
phase 2
Which phase has Early ventricular contraction and the first heart sound
phase 3
Describe phase 3
- AV valves close
Vibrations following closure of the AV valves
“Lub” (won’t ask about the heart sounds on the exam.) - No blood in or out (isovolumic ventricular contraction) (increase in pressure)
- Increasing pressure due to ventricular muscle contraction
- Concurrent atrial diastole
- No blood in or out (isovolumic ventricular contraction) (increase in pressure)
- Increasing pressure due to ventricular muscle contraction
- Concurrent atrial diastole
phase 3
The heart pumps: ventricular ejection
phase 4
what happens during phase 4
- Semilunar valves open (when pressure is high enough, these open.)
- Blood is ejected into arteries
- End-systolic volume (ESV): volume in ventricle at the end of ventricular contraction (a small amt of blood is left in the ventricle after the contraction
Ventricular relaxation and the second heart sound
phase 5
Describe phase 5
Arterial blood flows back towards heart
Semilunar valves shut–> second heart sound
“Dup”
Ventricular muscles relax pressure drops (still higher than atrial pressure)
No blood enters or exits (isovolumic ventricular relaxation)
AV valves open when ventricular pressure drops below atrial pressure
