The Cardiac Cycle

Question 1

How is work of the heart quantified?

Answer 1

It is quantified by Stroke Volume but also represented by pressure.

Question 2

If the ventricles are filling what phase are you in?

Answer 2

Mid to Late diastole

Question 3

If the ventricles are contracting what phase are you in?

Answer 3

Ventricular systole.

Question 4

What is characteristic of the late diastole phase?

Answer 4

1. Pressure in Aorta declining
2. Ventricular pressure near 0
3. Atria contract & Ventricular volume increases
4. Small increase in ventricular pressure

Question 5

What is the first heart sound?

Answer 5

When the AV valve closes.

Question 6

What is characteristic of the heart when the AV valve closes?

Answer 6

1. Pressure increases
2. Ventricular depolarization
3. Ventricles begin to contract
4. Ventricular pressure goes wayyyy up.

Question 7

What is Isovolumic contraction?

Answer 7

Where you have a constant volume because the pressure in ventricle is still less than the Aorta and higher than the Atria.

Question 8

Once Ventricular Pressure is HIGHER than Aortic pressure what happens?

Answer 8

1. The Aortic Valve opens and you enter the Ejection Phase

2. The volume in the ventricle goes down

Question 9

What is the critical point?

Answer 9

When the ventricular pressure comes back below aortic pressure and blood starts running back the Aortic valve closes.

Question 10

What is the second heart sound?

Answer 10

The Aortic Valve Closing.

Question 11

What happens once Ventricular pressure is LESS than Atrial pressure after the Aortic valve has closed?

Answer 11

The AV valve opens, and you have a early rushing of blood then full blown diastole.

Question 12

What is characteristic of the Early Systole Phase?

Answer 12

1. Ventricles depolarize and begin to “contract”
2. AV valve closes once pressure is right
3. Ventricular Volume is unchanged (Isovolumic contraction)
4. Once ventricular pressure is higher than aortic –> valve opens.

Question 13

What is Characteristic of the Ejection Phase?

Answer 13

1. S-T interval
2. Ventricular Volume decreases
3. Aortic pressure & Ventricular pressure increase together!

Question 14

What is Characteristic of Early Diastole Phase?

Answer 14

1. Ventricles begin to relax
2. Ventricular pressure declines
3. Aortic valve closes
4. Ventricular Volume is constant (Isovolumic relaxation)

Question 15

What is Characteristic of the filling phase?

Answer 15

1. Atrial pressure has increased during systole with venous return.
2. AV valve opens
3. Rapid filling (passive)
4. Late period of slow filling

Question 16

What is the Index of Preload?

Answer 16

End Diastolic Volume = volume in LV at end of diastole

Question 17

What is the Index of Afterload?

Answer 17

End Systolic Volume = volume in LV at end of systole

Question 18

How do you calculate Stroke Volume?

Answer 18

stroke volume = EDV – ESV

Question 19

How do you calculate Ejection Fraction?

Answer 19

ejection fraction = SV/ EDV

Question 20

How can you calculate Cardiac Output?

Answer 20

CO= SV x HR ……OR….. CO= MAP/TPR