Cardiac Function

Question 1

Required for the Ca2+ release from the SR that leads to Contraction

Answer 1

Influx of Ca2+

Question 2

In the heart, what is required for contraction?

-Distinguishing feature between cardiac and skeletal muscle

Answer 2

Extracellular calcium

Question 3

The mechanism by which an AP initiates Ca2+ release in cardiac muscle is called

Answer 3

Calcium-Induced Calcium Release (CICR)

Question 4

In a cardiac myocyte, increased intracellular Ca2+ is sensed by the Ca2+-sensitive

Answer 4

Ryanodine Receptors (RYR)

Question 5

Does NOT have CICR

Answer 5

Skeletal muscle

Question 6

SR calcium release in skeletal muscle is independent of

Answer 6

Ca2+

Question 7

In cardiac muscle, relaxation requires removal of Ca2+ from the cytoplasm. This occurs via

Answer 7

SERCA (back to SR) and NCX (out of cell)

Question 8

Returns Ca2+ to the Sarcoplasmic Reticulum (SR)

Answer 8

SERCA

Question 9

Calcium is removed from the cardiac cell via

Answer 9

NCX

Question 10

The intrinsic ability of myocardial cells to develop force at a given muscle length

Answer 10

Contractility (inotropy)

Question 11

Most mechanisms that affect inotropy affect how

Answer 11

Ca2+ is handled by the cell

Question 12

What are the three measures of ventricular function?

Answer 12

Stroke volume, Ejection fraction, and Cardiac Output

Question 13

The volume of blood ejected per contraction

-difference between EDV and ESV

Answer 13

Stroke Volume (SV = EDV - ESV)

Question 14

A way to look at the efficiency of ventricular contraction

Answer 14

Ejection fraction

Question 15

Determines the percent EDV ejected with each beat

Answer 15

Ejection Fraction

Question 16

The total volume of blood ejected by the heart in one minute

Answer 16

Cardiac Output (CO)

Question 17

How do we calculate Cardiac Output (CO)?

Answer 17

CO = SV x HR

Question 18

The biggest contributor to increased CO during exercise is

Answer 18

Increased HR

Question 19

In order for CO to increase, we also need some increase in

Answer 19

SV

Question 20

An increase in HR alone can cause CO to

Answer 20

Fall

Question 21

Which three factors influence stroke volume?

Answer 21

Preload, afterload, inotropy

Question 22

A cardiac myocyte can generate more force when it is

Answer 22

Stretched

Question 23

This stretch-induce inotropy is related to

Answer 23

Ca2+

Question 24

Increases TN-C Ca2+ affinity and stretch-activated Ca2+ channels

Answer 24

Stretch

Question 25

Stretch activated Ca2+ channels increase Ca2+ release from the

Answer 25

Sarcoplasmic Reticulum (SR)

Question 26

Increasing volume increases the

Answer 26

Maximal pressure

Question 27

Increasing the ventricular volume regulates the

Answer 27

Contractile force

Question 28

Does not change when preload is decreased

Answer 28

ESPVR

Question 29

The Frank-Starling law of the heart is that the SV is determined by the

Answer 29

LVEDV

Question 30

Increasing the PRELOAD (EDV) increases the

Answer 30

Force of contraction

Question 31

Increasing the force of contraction increases the

Answer 31

Stroke Volume (and thus CO)

Question 32

Increases as cardiac filling increases

Answer 32

SV

Question 33

Altering the preload DOES NOT affect the

Answer 33

ESPVR

Question 34

Increased venous return raises

Answer 34

EDV

Question 35

HR and atrial contraction are two factors which regulate the

Answer 35

Ventricular Preload

Question 36

Ventricular filling varies with

Answer 36

HR

Question 37

Atrial contraction is only an important component of ventricular filling when

Answer 37

HR is high or we have decreased ventricular compliance

Question 38

In the normal heart, PRELOAD correlates with

Answer 38

End-Diastolic Pressure (EDP)

Question 39

Affects the relationship between EDP and EDV

Answer 39

Compliance of the heart

Question 40

How easily the heart expands when it is filled with a volume of blood

Answer 40

Compliance

Question 41

The slope of the volume vs pressure plot is the

Answer 41

Compliance

Question 42

Ventricular compliance can be altered by

Answer 42

Disease

Question 43

Reflects stiffness of the ventricle

Answer 43

End-Diastolic Pressure-Volume Relationship (EDPVR)

Question 44

An increased EDPVR shows a

Answer 44

Stiff ventricle

Question 45

A stiff ventricle is harder to

Answer 45

Fill

Question 46

With a stiff ventricle, we have a higher pressure for any given

Answer 46

Volume

Question 47

With a stiff ventricle, we have a lower volume for any given

Answer 47

Pressure

Question 48

Under conditions of decreased compliance, the left ventricle does not

Answer 48

Relax

Question 49

When we have a stiff ventricle, we will have an increase in LVEDP, this leads to an increase in

Answer 49

Pulmonary capillary pressure

Question 50

Heart failure with preserved ejection fraction

Answer 50

“Diastolic” Heart Failure

Question 51

We can see concentric hypertrophy with

Answer 51

Hypertension and valvular disease

Question 52

Amyloidosis, glycogen storage diseases, hemochromatosis, and mutations in sarcoma result proteins can all result in

Answer 52

Restrictive cardiomyopathy

Question 53

Blood pressure in the thoracic vena cava near the right atrium

Answer 53

Central Venous Pressure (CVP)

Question 54

A major determinant of filling of the right ventricle

Answer 54

CVP

Question 55

CVP determines the

Answer 55

Preload

Question 56

The load against which the heart must contract to eject blood

Answer 56

Afterload

Question 57

A larger afterload causes

Answer 57

Decreased SV

Question 58

Makes the ventricle work harder to eject blood

Answer 58

Increased afterload

Question 59

Increasing the afterload DOES NOT affect the

Answer 59

ESPVR

Question 60

Decreases velocity and extent of fiber shortening

Answer 60

Increased afterload

Question 61

We can see chronic elevations in afterload with

Answer 61

Hypertension and aortic stenosis

Question 62

What are three examples of afterload reducing agents?

Answer 62

ACE inhibitors, Hydralazine, Sympathomimetics

Question 63

Determined by cellular mechanisms that affect the intrinsic contractility

Answer 63

Inotropy (contractility)

Question 64

Will INCREASE stroke volume independent of changes in preload or afterload

Answer 64

Increased inotropy

Question 65

Inotropy alters the slope of the

Answer 65

ESPVR

Question 66

Increases the intrinsic contractility

Answer 66

Inotropy

Question 67

The maximal pressure generated for any specific volume

Answer 67

Intrinsic contractility

Question 68

Inotropy causes the slope of the ESPVR to

Answer 68

Increase

Question 69

Sympathetic nervous system inner action of the heart influences

Answer 69

Inotropy

Question 70

Inotropy is also influenced by increased circulating

Answer 70

Catecholamines

Question 71

What is the effect on inotropy of sympathetic nervous system stimulation?

Answer 71

Increases inotropy

Question 72

Heart failure with reduced ejection fraction

Answer 72

Systolic Heart failure

Question 73

Activation of muscarinic ACh receptors decreases

Answer 73

cAMP

Question 74

What are three examples of positive inotropic agents for the heart?

Answer 74

Beta-agonists, phosphodiesterase-3 inhibitors, Digoxin