The Cardiac Cycle Flashcards
How is work of the heart quantified?
It is quantified by Stroke Volume but also represented by pressure.
If the ventricles are filling what phase are you in?
Mid to Late diastole
If the ventricles are contracting what phase are you in?
Ventricular systole.
What is characteristic of the late diastole phase?
- Pressure in Aorta declining
- Ventricular pressure near 0
- Atria contract & Ventricular volume increases
- Small increase in ventricular pressure
What is the first heart sound?
When the AV valve closes.
What is characteristic of the heart when the AV valve closes?
- Pressure increases
- Ventricular depolarization
- Ventricles begin to contract
- Ventricular pressure goes wayyyy up.
What is Isovolumic contraction?
Where you have a constant volume because the pressure in ventricle is still less than the Aorta and higher than the Atria.
Once Ventricular Pressure is HIGHER than Aortic pressure what happens?
- The Aortic Valve opens and you enter the Ejection Phase
2. The volume in the ventricle goes down
What is the critical point?
When the ventricular pressure comes back below aortic pressure and blood starts running back the Aortic valve closes.
What is the second heart sound?
The Aortic Valve Closing.
What happens once Ventricular pressure is LESS than Atrial pressure after the Aortic valve has closed?
The AV valve opens, and you have a early rushing of blood then full blown diastole.
What is characteristic of the Early Systole Phase?
- Ventricles depolarize and begin to “contract”
- AV valve closes once pressure is right
- Ventricular Volume is unchanged (Isovolumic contraction)
- Once ventricular pressure is higher than aortic –> valve opens.
What is Characteristic of the Ejection Phase?
- S-T interval
- Ventricular Volume decreases
- Aortic pressure & Ventricular pressure increase together!
What is Characteristic of Early Diastole Phase?
- Ventricles begin to relax
- Ventricular pressure declines
- Aortic valve closes
- Ventricular Volume is constant (Isovolumic relaxation)
What is Characteristic of the filling phase?
- Atrial pressure has increased during systole with venous return.
- AV valve opens
- Rapid filling (passive)
- Late period of slow filling
