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Flashcards in C- Heart as a Pump Deck (21):
1

Cardiac output =

heart rate x stroke volume

CO = HR x SV

2

Cardiac Output (CO) is the volume of blood pumped per minute by the heart (_______ at rest)

~5 L/min

3

stroke volume

amount of blood pumped per beat

4

stroke volume factors

Preload (venous return)

Afterload = resistance to flow (normally aortic pressure)

Strength of contraction

5

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

Strength of contraction mechanisms

6

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

PRELOAD

7

The load against which a muscle contracts.

AFTERLOAD

8

Difference between SPVR and EDPVR
Represents ACTIVE tension (i.e., that generated by contraction)
Ascending & descending limbs
represented by?

Ventricular Function (Starling) Curve

9

Heart always functions on the ascending limb of the __________ (Starling) curve

ventricular function

Frank-Starling Law of the Heart- What comes in, must go out.

10

Heart responds to an increase in end diastolic volume (EDV) by increasing the force of ________

contraction

Frank-Starling Law of the Heart- What comes in, must go out.

11

Starling’s Law is an_________ property of the heart.

INTRINSIC

-independent of autonomic nervous system regulation
-analogous to, and dependent on, the sarcomere length-tension relationship

12

-independent of autonomic nervous system regulation
-analogous to, and dependent on, the sarcomere length-tension relationship
-Parts of what law?

Starling’s Law, an INTRINSIC property of the heart.

13

Ejection Fraction (EF) = _____________

Proportion ejected at each beat

pv loop ex:
= SV/EDV
= (EDV – ESV)/EDV = 70/120 = 58%

14

Factors that affect preload

blood volume
filling pressure & time
resistance to filling
right atrial pressure, AV valve stenosis
Ventricular compliance

15

Factors that affect afterload

Aortic pressure is the major determinant of afterload

defined as wall stress, so wall thickness and radius also affect afterload

Aortic stenosis can also affect afterload

16

hypertension increases________

afterload

17

For left ventricle, preload ~ _____________

end diastolic volume.

18

For left ventricle, afterload ~ _________

aortic pressure

19

Increased afterload _______ stroke volume on next beat

decreases

20

Force of contraction independent of fiber length

describes systolic function of heart
Sympathetic tone is the biggest factor affecting inotropy


INOTROPY (CONTRACTILITY):

21

Changes in________ describe new ventricular function (Starling) curves

inotropy