Physiologic Heart Function

Question 1

Cardiac index

Answer 1

the hemodynamic measurement equivalent of cardiac output

Question 1

What does cardiac output vary by

Answer 1

body size

Question 2

Why is cardiac output diminished in heart failure

Answer 2

the left ventricle is weakened and cannot properly pump

Question 3

What is the key concept of heart failure

Answer 3

the stroke volume is compromised, perfusion is reduced, CO decreased

Question 4

Preload

Answer 4

the volume of blood still in the heart at the end of diastole

Question 5

End diastolic volume

Answer 5

blood empties into the right ventricle

Question 6

Afterload

Answer 6

the amount of resistance the ventricle must overcome in order to pump blood out of the heart

Question 7

When is there greater pulmonary resistance

Answer 7

greater afterload against the right ventricle

Question 8

When is there greater systemic arterial vascular resistance

Answer 8

greater afterload against the left ventricle

Question 9

Cardiac contractility

Answer 9

the myocardium’s ability to stretch and contract in response to filling the heart with blood

Question 10

What do actin and myosin action create

Answer 10

force of contraction

Question 11

What can afterload do to contractility

Answer 11

negatively affect contractility by increasing the heart’s workload

Question 12

What is cardiac contractility influenced by

Answer 12

ANS, acid-base balance, elctrolytes

Question 13

Inotropic function

Answer 13

the force of contraction of cardiac muscle

Question 14

What is inotropic function influenced by

Answer 14

the amount of calcium available for activation of cardiac muscle filaments

Question 15

Positive inotropic effect

Answer 15

sympathetic stimulation can increase force

Question 15

Chronotropic function

Answer 15

the heart rate

Question 15

Epinephrine inotropic and chronotropic effects

Answer 15

positive for both, makes the heart beat faster and stronger (sympathetic stimulation)

Question 16

Frank-starling law

Answer 16

explains the relationship between cardiac contractility, preload, afterload, SV, and CO

Question 17

Why do the ventricles adjust pumping force

Answer 17

to accommodate changing levels of preload and afterload

Question 18

Starling’s capillary forces

Answer 18

2 opposing forces present at every capillary bed (hydrostatic and oncotic/osmotic)

Question 19

Hydrostatic pressure

Answer 19

fluid in the blood attempting to force fluid out, into the intracellular/interstitial spaces

Question 20

Oncotic pressure

Answer 20

pull fluid from intracellular/interstitial spaces back into the vessel

Question 21

What is edema caused by

Answer 21

increased hydrostatic pressure in capillary causing imbalance and fluid leaks