BSI 2 Lecture 14-15: Cardiac Cycle

Question 1

What is the function of the atria?

Answer 1

To shuttle blood to the ventricle

Question 2

What happens to 60-90% of the blood when the AV valves are open?

Answer 2

They pass straight through to the ventricles

Question 3

What happens when the atria contract?

Answer 3

They push more blood into the ventricles (10-40%)

Question 4

What happens when atria enhance the amount of blood in ventricles?

Answer 4

They enhance ventricular pumping

Question 5

What is the function of the right ventricle?

Answer 5

To pump blood through pulmonary circulation

Question 6

What is the function of the left ventricle?

Answer 6

To pump blood through systemic circulation

Question 7

Do valves open passively or actively?

Answer 7

Passively

Question 8

What opens valves?

Answer 8

Foward pressure

Question 9

What closes valves?

Answer 9

Backwards pressure

Question 10

Which valves have chordae tendinae and papillary muscle?

Answer 10

Atrioventricular valves

Question 11

What are the steps of the cardiac cycle?

Answer 11

1) atrial contraction
2) isovolumetric contraction
3) ejection
4) isovolumetric relaxation
5) ventricular filling

Question 12

What is systole?

Answer 12

contraction phase

Question 13

What is diastole?

Answer 13

Relaxation phase

Question 14

What is pulse pressure?

Answer 14

Systolic BP - Diastolic BP

Question 15

What is end diastolic volume?

Answer 15

the amount of blood in the ventricle once it is filled just before it contracts

Question 16

What is an important determinant of EDV?

Answer 16

Venous return

Question 17

What is end systolic volume (ESV)?

Answer 17

The volume of blood in the ventricle at the end of systole

Question 18

What is stroke volume?

Answer 18

The volume of blood pumped out of the ventricle per contraction

Question 19

What determines stroke volume?

Answer 19

preload, afterload, and contractility

Question 20

What is ejection fraction?

Answer 20

The fraction of EDV that was pumped out of the left ventricle per contraction. SV/EDV * 100

Question 21

What is cardiac output?

Answer 21

The amount of blood pumped out of the left ventricle per minute. (heart rate * SV) = CO

Question 22

What is venous return?

Answer 22

The amount of blood returned to the heart

Question 23

What is preload?

Answer 23

It is the stretch of the heart before contraction. It is mainly affected by end diastolic volume. The great the preload, the greater the contractility.

Question 24

What is afterload?

Answer 24

The amount of pressure the ventricles have to overcome to pump blood out of the heart. If pulmonary pressure or aortic pressure is higher than the pressure of the ventricles, they will have an increased afterload.

Question 25

What is contractility?

Answer 25

The intrinsic ability of cardiac muscle to produce tension, independent of fiber (sarcomere) length

Question 26

What is the primary determinant of contractility?

Answer 26

Intracellular calcium

Question 27

What is a chronotropic effect?

Answer 27

Anything effecting heart rate

Question 28

What is an ionotropic effect?

Answer 28

Anything affecting heart contractility

Question 29

What is cardiac reserve?

Answer 29

the work that the heart is able to perform beyond that required of it under basal/resting conditions

Question 30

What is Pressure-Rate product?

Answer 30

An indirect index of myocardial O2 consumption (how hard the ventricle is working). HR x SBP (or MAP)

Question 31

What are the heart sounds?

Answer 31

Sound 1: closing of AV valves. Sound 2: closing of semilunar valves