403 T/f

Front 1

Compared to the fast response myocardial fiber, the resting potential of the slow fiber is more positive.

Back 1

True

Front 2

Slow response fibers are found in the natural pacemaker of the heart

Back 2

True

Front 3

The resting myocardial membrane is more permeable to sodium compared to the potassium ion

Back 3

False, the potassium ion is more permeable

Front 4

For cardiac cells, elevated extracellular potassium concentration can depolarize membrane potential and inactivate the fast sodium channels

Back 4

True

Front 5

All normal heart muscle cells in isolation can beat on their own

Back 5

True

Front 6

Lung stretch receptors are part of a reflex where heart rate increases due to lung deflation

Back 6

False, due to inflation

Front 7

Carotid chemoreceptor stimulation will lead to a decreased heart rate if ventilation is maintained at a constant level

Back 7

True

Front 8

Heart rate is expected to increase due to volume loading as well as volume depletion

Back 8

True

Front 9

In a resting normal human, administration of propranolol is expected to lead to an increase in heart rate when given without other drugs

Back 9

False

Front 10

Increasing transmural pressure in an artery will lead to a dilation of that artery due to the myogenic mechanism

Back 10

False

Front 11

The volume of fluid returned to the circulation via the lymphatics per minute equals cardiac output

Back 11

False

Front 12

An increase in arterial blood pressure from 100 to 125 mm Hg is expected to lead to an increase in heart rate

Back 12

False

Front 13

Preload of the myocardium can be measured by end-diastolic volume

Back 13

True

Front 14

Afterload of the right ventricle can be measured by pulmonary arterial pressure

Back 14

False

Front 15

Laminar flow is associated with cardiac murmurs

Back 15

False, turbulent flow?

Front 16

The "T" wave of the electrocardiogram is associated with atrial repolarization

Back 16

False

Front 17

Atrial fibrillation is incompatible with life and leads to loss of consciousness within a few seconds

Back 17

False

Front 18

The slow response cardiac fiber has a pronounced flat plateau in phase 2 where calcium and potassium fluxes are balanced

Back 18

False, it looks like a hump

Front 19

Most of the blood in the systemic vascular bed is located in the arterial rather than the venous side of the circulation.

Back 19

False, most is in the veins

Front 20

Capillary blood flow is nonpulsatile but can vary periodically due to vasomotion

Back 20

True

Front 21

The ____________ hypothesis explains vascular bed autoregulation as being due to production of a metabolite which is proportional to metabolism and is a vasodilator.

Back 21

metabolic

Front 22

_________ law of the capillaries explains fluid movement across the capillary wall as being a balance of hydrostatic and osmotic forces

Back 22

Starling

Front 23

The _____ node is the natural pacemaker of the heart

Back 23

SA

Front 24

An enhancement of cardiac _________ is said to occur when the ventricular function curve shifts to the left or the rate of change of left ventricular pressure increases.

Back 24

contractility

Front 25

The _______ reflex is responsible for heart rate changes due to distention or stretch of the right atrium

Back 25

Bainbridge

Front 26

The ________ reflex causes a heart rate increase due to a fall in arterial blood pressure

Back 26

baroreceptor

Front 27

___________ law describes the proportionality between laminar flow level and the pressure drop in a tube.

Back 27

Poiseville

Front 28

The valve between the left atrium and the left ventricle is called the _____ valve

Back 28

mitral

Front 29

The atrioventricular valves are attached by ligaments called chordae tendinae to __________ mucles

Back 29

papillary

Front 30

The __________________ cardiac nerves release the substance acetylcholine.

Back 30

parasympathetic

acetylcholine is associated with relaxation

Front 31

Depolarizing a myocardial cell to +30mv membrane potential leads to reduction (inactivation gate closing) of sodium ion influx into the cell

Back 31

True

Front 32

A reduction in the normal extracellular sodium ion concentration from the normal 145 mM/L to 100 mM/L is expected to cause a decrease in the resting membrane potential

Back 32

False

Front 33

The valve between the left atrium and the left ventricle is the tricuspid

Back 33

True

Front 34

The free extracellular calcium ion concentration is the agent responsible for the contractile state of the myocardium

Back 34

False

Front 35

Both blood transfusion and hemorrhage from a normal state is expected to lead to an increase in heart rate

Back 35

True

Front 36

Respiratory sinus dysrhythmia is an abnormal condition only seen in patients

Back 36

False

Front 37

Carotid chemoreceptor stimulation decreases heart rate

Back 37

True, they are part of the parasympathetic system

Front 38

A high level of hydraulic filtering of the arterial system (high RC product) lowers the workload of the heart for a given mean arterial pressure and cardiac output

Back 38

True

Front 39

Capillary hydrostatic pressure elevation is expected to promote capillary filtration

Back 39

True

Front 40

The lymphatic circulation eventually drains into the venous circulation

Back 40

True

Front 41

Increased flow in an arteriole stimulates the endothelium and leads to vasodilation

Back 41

True

Front 42

The lymphatic circulation eventually drains into the venous circulation

Back 42

True

Front 43

Stimulating the parasympathetic nerves connected to the heart is expected to increase the heart rate

Back 43

False

Front 44

Lung inflation is expected to lead to a reflex decrease in heart rate

Back 44

False

Front 45

According to the linear vascular function curve model, an increase in cardiac output with all vascular parameters constant is expected to lead to a decrease in central venous pressure

Back 45

True

Front 46

When central venous pressure becomes subatmospheric, cardiac output is essentially limited to the value at atmospheric pressure (0 mm Hg)

Back 46

True

Front 47

Coupling of the heart and vasculature refers to the intersection of the cardiac function curve with cardiac output versus arterial pressure curve

Back 47

False

Front 48

From Bernoulli's equation, one would expect that if there is a narrowing in an artery, the higher velocity will lead to a lower static pressure near the narrowing

Back 48

True

Front 49

Bernoulli''s equation does not apply when there is a significant pressure drop due to viscous drag between two points

Back 49

True

Front 50

If there is a laminar flow and a pressure drop in a tube due to viscosity, then Bernoulli's equation applies at all points

Back 50

False

Front 51

_____________________ is the autoregulation mechanism explaining reactive hyperemia

Back 51

Metabolic hypothesis

Front 52

The drug _____ blocks the parasympathetic nervous system and can be used in normals to study rate regulation

Back 52

Atropine

Front 53

The _______ node provides a delay between atrial and ventricular excitation

Back 53

AV

Front 54

The ______________________ carries the electrical excitation from atria to the ventricles

Back 54

bundle of His

Front 55

Vascular smooth muscle cells contract bi stimulating calcium ion release from an intracellular storage site

Back 55

True

Front 56

Hypoxia can stimulate chemoreceptors and lead to a steady state increase in the heart rate

Back 56

False

Front 57

In ventricular fibrillation, the heart is randomly activated and must be strongly stimulated to synchronous activity

Back 57

True

Front 58

Coronary artery blood flow is macimum during diastole and minimum during systole

Back 58

True

Front 59

A decrease in blood volume increases heart rate

Back 59

True

Front 60

An increase in baroreceptor nerve activity occurs with a fall in arterial blood pressure

Back 60

False

Front 61

A unidirectional block of the cardiac depolarization refers to heart muscle which due to lack of coronary perfusion, is completely incapable of electrical depolarization

Back 61

False

Front 62

Wolff-Parkinson-White syndrome is an example of abnormal cardiac impulse re-entry

Back 62

True

Front 63

Applying elevated external pressure to the bbaroreceptor area in the neck is expected to lead to an increase in heart rate

Back 63

False

Front 64

The transient response to sympathetic stimulation is slower than the response to vagal stimulation

Back 64

True

Front 65

Autoregulation refers to the ability of a tissue to keep local blood flow constant

Back 65

True

Front 66

Cardiac muscle, like skeletal muscle, has an action potential a few milliseconds in duration

Back 66

False

Front 67

The papillary muscles connect the semilunar valves to the ventricular myocardium

Back 67

False

Front 68

Lowering colloid osmotic pressure below the normal level will favor capillary filtration

Back 68

True

Front 69

Baroreceptors respond to both the mean as well as fluctuations in pressure from the mean level

Back 69

True

Front 70

Turbulent blood flow causes heart murmurs

Back 70

True

Front 71

Smooth muscle cells lack troponin

Back 71

True

Front 72

Fast sodium channels are important in smooth muscle cell depolarization

Back 72

False (cardiac muscle)

Front 73

________________ refers to enhanced blood flow in proportion to occlusion time periods in support of the metabolic hypothesis of autoregulation

Back 73

Reactive hyperemia

Front 74

The vagus nerve releases the chemical substance _____________ in the vicinity of the cardiac nodal tissue.

Back 74

Acetylcholine

Front 75

The cardiac sympathetic fibers can be blocked by the drug _______

Back 75

propranolol

Front 76

_______ triangle

Back 76

Einthoven

Front 77

Unipolar limb leads

Back 77

+90, -30, -150 degrees from horizontal

Front 78

________ equation links extracellular and intracellular concentration of ions to membrane potential

Back 78

Nernst