Cardiac Cycle

Question 1

Blood moves according to what gradient?

Answer 1

down pressure gradient

Question 2

Where do pressure changes occur?

Answer 2

• left atria
• left ventricle
• left aorta

Question 3

Where do volume changes occur?

Answer 3

ventricle

Question 4

Where do electrical changes occur?

Answer 4

atria and ventricle

Question 5

What are the 7 phases of the cardiac cycle?

Answer 5

1. atrial systole
2. ventricular isovolumetric contraction
3. rapid ventricular ejection
4. slow ventricular ejection
5. ventricular isovolumetric relaxation
6. ventricular filling
7. diastasis

Question 6

What occurs in phase 1 of the cardiac cycle?

Answer 6

1. P-wave: atrial depolarization precedes and triggers atrial contraction
2. a wave: developed atrial pressure
3. blood moves from atrial chamber and fill the ventricle (increase pressure)
4. AV valves close -> 1st heart sound ->ends phase 1

Question 7

What occurs between phase 1 and 2?

Answer 7

no change in blood volume in chambers (isovolumic)

Question 8

What occurs in phase 2 of the cardiac cycle?

Answer 8

1. QRS wave: ventricular depolarization precedes and triggers rapid ventricular contraction
2. contraction causes rise in developed ventricular pressure
3. input (A-V) and output (aortic) -> valves clsoe, no blood moves
4. aortic valves open -> phase 2 ends

Question 9

What occurs in phase of 3 the cardiac cycle?

Answer 9

1. blood ejected from the ventricle
2. ventricular contraction is transmitted mechanically to the atria producing the c wave
3. t wave: ventricular repolarization initiates ventricular relaxation -> end of phase 3

Question 10

What occurs in phase 4 of the cardiac cycle?

Answer 10

1. relaxation causes decrease in ventricular pressure
2. ventricle slowly empties
3. return of blood begins artrial filling and increased atrial pressure
4. aortic valve closes -> 2nd heart sound -> end of phase 4

Question 11

What occurs in phase 5 of the cardiac cycle?

Answer 11

1. input and output valves are closed, no ventricular blood moves
2. AV valves opens -> end of phase 5

Question 12

What occurs in phase 6 of the cardiac cycle?

Answer 12

1. ventricular pressure is below atrial
2. with AV valve open, atrial blood rapidly flows into the ventricle (turbulant sound)
3. 3rd heart sound caused by rapid turbulant flow

Question 13

What occurs in phase 7 of the cardiac cycle?

Answer 13

1. AV valve is open, venous blood is slowly filling atrial and ventricular chambers
2. decreased, slow ventricular filling
3. aortic pressure slowly declines
4. atrial contraction-> end of phase 7 and back to phase 1

Question 14

What is stroke volume?

Answer 14

end diastolic volume - end systolic volume

Question 15

As the volume of the ventricular tissue increases, what happens to the length and pre-load?

Answer 15

they both increase

Question 16

Increasing length by stretching increases what?

Answer 16

passive force

Question 17

Chamber pressure increases with what?

Answer 17

contractility

Question 18

In the pressure volume loop, when does ventricular filling occur?

Answer 18

between when the mitral valve opens and when the mitral valve closes

Question 19

In the pressure volume loop, when does isovolumetric contraction occur?

Answer 19

when mitral valve closes and aortic valve opens

Question 20

In the pressure volume loop, when does ventricular ejection occur?

Answer 20

when aortic valve opens and aortic valve closes

Question 21

In the pressure volume loop, when does isovolumetric relaxation occur?

Answer 21

when aortic valve closes and mitral valve opens