Cardiovascular Physiology 17

Question 1

What two parts can the Cardiac Cycle be divided into?

Answer 1

Systole and Diastole

Question 2

What are Systole and Diastole defined by?

Answer 2

The ventricles

Question 3

What is Systole?

Answer 3

Ventricular contraction and blood ejections

Question 4

What is Diastole?

Answer 4

Ventricular relaxation and filling of the ventricles with blood

Question 5

What is the Cardiac cycle bound by?

Answer 5

The beginning of one heartbeat to the beginning of the next

Question 6

What is the length of the cardiac cycle?

Answer 6

800 msec

Question 7

What is the length of Systole and Diastole?

Answer 7

Systole: 300 msec
Diastole: 500 msec

Question 8

What are the two phases that Ventricular Systole can be divided into?

Answer 8

• Isovolumetric ventricular contraction

* Ventricular ejection

Question 9

What is the state of the heart valves during Isovolumetric Ventricular Contraction?

Answer 9

All heart valves are closed

Question 10

What occurs during Isovolumetric Ventricular Contraction during Systole?

Answer 10

All heart valves are closed, the blood volume remains constant, pressure rise and the muscle develops tension but cannot shorten

Question 11

What occurs during the Ventricular Ejection phase of systole?

Answer 11

Pressure in the ventricles exceeds that in arteries, semilunar valves open and blood is ejected into the artery. Muscle fibers of the ventricles shorten

Question 12

Which valves open during Ventricular Ejection?

Answer 12

Semilunar valves to the Pulmonary artery and the Aorta

Question 13

What keeps the AV valves closed during ventricular ejection?

Answer 13

The chordae tendineae and the papillary muscles

Question 14

What is Stroke Volume?

Answer 14

The volume of blood ejected from each ventricle during systole

Question 15

What is the difference between the ventricles during systole?

Answer 15

When the left ventricle contracts it contract with more force

Question 16

Why doesn’t the heart eject its entire volume of blood during contraction?

Answer 16

In order to allow the heart to change the volume of blood that it pumps out depending on the body’s needs

Question 17

What are the two phases of Ventricular Diastole?

Answer 17

• Isovolumetric ventricular relaxation

* Ventricular filling

Question 18

Which valves close during Diastole?

Answer 18

The Semilunar valves

Question 19

What is the state of the heart valves during Isometric Ventricular Relaxation during Diastole?

Answer 19

Both the AV and Semilunar valves are closed

Question 20

What occurs during Isovolumetric Ventricular Relaxation?

Answer 20

All heart valves close, blood volume remains constant and pressures drop

Question 21

What causes Ventricular Filling?

Answer 21

The pressure in the atria filling with blood that exceeds the pressure in the ventricles

Question 22

What occurs during Ventricular Filling of Diastole?

Answer 22

AV valves open, blood flows into ventricles from atria. Ventricles receive blood passively

Question 23

What is the state of the valves during Ventricular Filling?

Answer 23

AV valves are open and Semilunar valves are closed

Question 24

What is the contraction state of both the atria and the ventricles during passive ventricular filling?

Answer 24

Both the atria and ventricles are relaxed

Question 25

What completes ventricular filling?

Answer 25

The contraction of the atria

Question 26

What is Atrial Kick?

Answer 26

Atria contraction at the end of ventricular filling

Question 27

What valves must be open and close in order for the ventricles to receive blood from the atrium?

Answer 27

The AV valves must be open and the semilunar valves must be closed

Question 28

What occurs in Atrial Systole?

Answer 28

The atrial contraction forces the last amount of blood into the relaxed ventricle, completing ventricular filling

Question 29

What happens after Atrial Kick?

Answer 29

The atria remain in Diastole for the remainder of the cardiac cycle

Question 30

What occurs after Atrial Systole is finished?

Answer 30

The ventricles enter systole

Question 31

What closes the AV valves?

Answer 31

The pressure gradient created when the ventricular valves contract

Question 32

What occurs during Isovolumetric contraction?

Answer 32

The heart contracts but does not create enough pressure to open the semilunar valves

Question 33

What stage occurs after Isovolumetric contraction?

Answer 33

Ejection

Question 34

What occurs in Ejection?

Answer 34

The ventricles contract hard enough to cause enough pressure to open the semilunar valves and blood is ejected into the arteries

Question 35

What keeps the AV valves closed during Ejection?

Answer 35

Chordae Tendineae and the Papillary muscles

Question 36

What occurs after the ejection phase?

Answer 36

The ventricles enter Diastole

Question 37

What closes the semilunar valves during Diastole?

Answer 37

The blood flowing back closes them

Question 38

What stage occurs after Ventricular Systole Ejection?

Answer 38

Isovolumetric Relaxation of ventricular Diastole

Question 39

When does Passive Ventricular Filling occur?

Answer 39

After Isovolumetric relaxation where blood flows from the atria into the ventricles

Question 40

What occurs after Isovolumetric Relaxation?

Answer 40

Passive Ventricular filling