pump

Question 1

Cardiac Output (CO) is the

Answer 1

volume of blood pumped per minute by the heart (~5 L/min at rest)

Question 2

CO =

Answer 2

HR x SR

cardiac output = heart rate x stroke volume

Question 3

Stroke volume is the

Answer 3

amount of blood pumped per beat.

Representative numbers for “average” person at rest
HR ~ 70 beats/min
SV ~ 70 ml/beat
CO = HR x SV ~ 4.9 L/min

Question 4

two ways to control cardiac output

Answer 4

1. HR

2. SV

Question 5

heart rate is set by

Answer 5

sinoatrial (SA) node

It is highly regulated by autonomic nervous system and humoral agents

Question 6

Stroke volume is dependent on

Answer 6

1. preload
2. afterload
3. strength of contraction

Question 7

preload is the

Answer 7

venous return

Question 8

afterload is the

Answer 8

resistance to flow (normally aortic pressure)

Question 9

Strength of contraction

Answer 9

Length-dependent intrinsic regulation (Starling’s Law) and length-independent regulation via sympathetic nervous system

Question 10

During diastole (filling phase), the mitral valve is

Answer 10

open

Question 11

during systole, (contraction phase) the aortic valve is

Answer 11

closed

Question 12

EDPVR stands for

Answer 12

end diastolic pressure volume relationship

Question 13

EDPVR is the

Answer 13

Pressure-volume relationship during filling of heart BEFORE contraction

Question 14

EDPVR corresponds to

Answer 14

passive elastic properties of ventricle (slope is inverse of compliance)

Question 15

EDPVR slope is

Answer 15

shallow in normal physiological range (high compliance)

Question 16

The EDPVR represents the

Answer 16

PRELOAD on the left ventricle

Question 17

SPVR stands for

Answer 17

systolic pressure volume relationship

Question 18

SVPR pressure-volume relationship at

Answer 18

peak of isometric contraction

Question 19

SVPR represents the

Answer 19

Maximum pressure that can be developed for a given set of circumstances

Question 20

SVPR curve is

Answer 20

Steeper than EDPVR – pressure increases a lot for small changes in volume

Question 21

SVPR includes

Answer 21

active plus passive properties

Question 22

preload is the

Answer 22

1. volume entering the ventricles

2. The load/length to which a muscle is subjected before shortening.

Question 23

afterload is the

Answer 23

1. resistance that the left ventricle must overcome to circulate blood
2. the load against which a muscle contracts

Question 24

preload range

Answer 24

values lie along the diastolic pressure-volume curve.

Question 25

preload for left ventricle

Answer 25

~ end diastolic volume.

Question 26

afterload for the left ventricle is

Answer 26

~aortic pressure

Question 27

afterload range

Answer 27

(without changes in contractility) lie along the systolic pressure-volume curve

Question 28

Ventricular Function (Starling) curve

Answer 28

1. Difference between SPVR and EDPVR
2. Represents ACTIVE tension (i.e., that generated by contraction)
3. Ascending & descending limbs
4. Analogous to sarcomere length-tension curves
5. Families of Starling curves for different inotropic states
6. Multiple ways to plot (y-axis = pressure, tension, cardiac output, stroke volume; x-axis = volume or length)

Question 29

Starling’s Law is an _____ property of the heart.

Answer 29

INTRINSIC

Question 30

starling’s law is independent of

Answer 30

autonomic nervous system regulation

Question 31

starling’s law is analogous to

Answer 31

and dependent on, the sarcomere length-tension relationship