C- Heart as a Pump Flashcards Preview

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

Cardiac output =

A

heart rate x stroke volume

CO = HR x SV

2
Q

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

A

~5 L/min

3
Q

stroke volume

A

amount of blood pumped per beat

4
Q

stroke volume factors

A

Preload (venous return)

Afterload = resistance to flow (normally aortic pressure)

Strength of contraction

5
Q

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

A

Strength of contraction mechanisms

6
Q

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

A

PRELOAD

7
Q

The load against which a muscle contracts.

A

AFTERLOAD

8
Q

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

A

Ventricular Function (Starling) Curve

9
Q

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

A

ventricular function

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

10
Q

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

A

contraction

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

11
Q

Starling’s Law is an_________ property of the heart.

A

INTRINSIC

  • independent of autonomic nervous system regulation
  • analogous to, and dependent on, the sarcomere length-tension relationship
12
Q
  • independent of autonomic nervous system regulation
  • analogous to, and dependent on, the sarcomere length-tension relationship
  • Parts of what law?
A

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

13
Q

Ejection Fraction (EF) = _____________

A

Proportion ejected at each beat

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

14
Q

Factors that affect preload

A
blood volume
filling pressure & time
resistance to filling
  right atrial pressure, AV valve stenosis
  Ventricular compliance
15
Q

Factors that affect afterload

A

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
Q

hypertension increases________

A

afterload

17
Q

For left ventricle, preload ~ _____________

A

end diastolic volume.

18
Q

For left ventricle, afterload ~ _________

A

aortic pressure

19
Q

Increased afterload _______ stroke volume on next beat

A

decreases

20
Q

Force of contraction independent of fiber length

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

A

INOTROPY (CONTRACTILITY):

21
Q

Changes in________ describe new ventricular function (Starling) curves

A

inotropy