Regultion Of Cardiac Output

Question 1

CO =

Answer 1

SV * HR

Question 2

SV =

Answer 2

EDV - ESV

Question 3

heart rate is regulated by

Answer 3

The ratio of sympathetic vs parasympathetic inputs

Question 4

Flow =

Answer 4

Liters/min

Cardiac output

Question 5

Norepinephrine’s action

Answer 5

Positive chronotropic
Effect
Binds to beta-1 adrenergic receptors in SA node to increase phase 4 depolarization
Reuptake is relatively slow

Question 6

Chronotropic effect

Answer 6

Increase in heart rate

Question 7

Parasympathetic actions on heart rate

Answer 7

Ach binds to muscuricnisympathci receptors on pacemaker cells
 -modifying funny Na+ conductance
 - modifying K+ conductance
 -modifying Ca++ channel threshold
Negative chronotropic effect

Question 8

Typically increases in heart rate are coupled with changes in

Answer 8

Ventricular function

Question 9

Positive lusitropic effects

Answer 9

Increased rate of relaxation

Question 10

Intrinsic regulation

Answer 10

Mechanical properties of cardiac muscle

Question 11

Extrinsic regulation

Answer 11

Effects of sympathetic innervation, hormonal, and alteration of blood gases and pH

Question 12

The active tension is dependent upon the

Answer 12

Sharing length of the sarcoma refs at the time of activation.

Question 13

Total tension =

Answer 13

Passive tension + active tension

Question 14

External constraints include

Answer 14

EDV, aortic pressure

Question 15

Preload

Answer 15

The stretch on the cardiac muscle that occurs during the relaxed state

Question 16

Isometric force generation is dependent upon

Answer 16

The starting length

Question 17

Frank - Starlng mechanisms important mechanism for

Answer 17

Equalizing outputs between right and left ventricles

Typically they heart operates to the left Lmax

Question 18

Isotonic contractioase

Answer 18

Volume ejection

When total muscle force exceeds the external load the muscle begins to shorten

Question 19

Afterload

Answer 19

When ventricular force (pressure) > the aortic pressure, the aortic alive opens

Question 20

ESV of the muscle after contractio is directly related to

Answer 20

The afterload and contractility and not the preload

Question 21

Increases in aortic pressure

Answer 21

Decrease stroke volume

Question 22

Decrease in aortic pressure

Answer 22

Increase stroke volume

Question 23

Contractility

Answer 23

The performance of the heart at a given preload and afterload
Reflects the activity taking place at the interacting cross bridges
Determined by changes in intracellular Ca++ and rate of contra lie protein interaction

Question 24

Inotropic changes

Answer 24

Changes in contractility

Question 25

Thyroid hormone

Answer 25

Enhance Ca++ reuptake and hypertrophy

Question 26

Increases in CO2 and the associated decrease in cellular Ph cause a

Answer 26

Declines in myocardial performance

Question 27

Myocardial ischemia that occurs during coronary occlusion contributes to

Answer 27

A rapid decline in myocardial force

Question 28

Negative inotropic effects

Answer 28

Heart failure