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Chapter 20 - The Heart

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1

Artery is to ________ as vein is to ________.

A) efferent; afferent

B) afferent; efferent

C) toward; away

D) afferent; away

E) efferent; away

A) efferent; afferent (afferent arrives, efferent exits)

2

The heart beats approximately ________ times each day.

A) 1,000

B) 10,000

C) 100,000

D) 1,000,000

E) 10,000,000

C) 100,000

3

The heart pumps approximately ________ liters of blood each day.

A) 8,000

B) 15,000

C) 20,000

D) 50,000

E) 100,000

A) 8,000

4

Excess fluid in the ________ causes cardiac tamponade.

A) pericardial cavity

B) visceral pericardium

C) apex of heart

D) left ventricle

E) both atria

A) pericardial cavity (potential space between the parietal and visceral surfaces of the pericardial sac)

5

What is normally found in the pericardial cavity?

  1. synovial fluid
  2. air
  3. pericardial fluid
  4. blood

C. pericardial fluid

6

Which of the following descriptions matches the term near the left fifth intercostal space?

A) pericardial cavity

B) visceral pericardium

C) apex of heart

D) aorta

E) right atrium

C) apex of heart

7

The term used to describe fluid collecting in the pericardial cavity that restricts the movement of the heart is known as

A) cardiac tamponade.

B) mitral valve prolapse.

C) pleural effusion.

D) cardiomyopathy.

E) pericarditis.

A) cardiac tamponade

8

The interventricular sulci and coronary sulcus

A) contain fat.

B) contain arteries.

C) contain veins.

D) are grooves on the surface of the heart.

E) All of the answers are correct.

E) All of the answers are correct.

9

Blood leaves the right ventricle by passing through the

A) aortic valve.

B) pulmonary valve.

C) mitral valve.

D) tricuspid valve.

E) bicuspid valve.

B) pulmonary valve (dirty blood on way to lungs)

10

Intercalated discs serve to transfer ________ from cell to cell.

A) ionic currents

B) action potentials

C) the force of contraction

D) electrical signals

E) All of the answers are correct.

E) All of the answers are correct.

11

Why is it important for impulses from the atria to be delayed at the AV node before they pass into the ventricles?

  1. So the atria can relax before the ventricles contract
  2. So the ventricles can finish filling
  3. So the AV valves can close before the ventricles contract
  4. So the AV bundle can receive the stimulus

B. So the ventricles can finish filling

12

The coronary sulcus is a groove that

A) marks the border between the atria and ventricles.

B) marks the boundary line between the right and left ventricles.

C) marks the boundary line between the right and left atria.

D) separates the atrioventricular valves from the atria.

E) separates the coronary arteries from the coronary veins.

A) marks the border between the atria and ventricles (the big sulcus)

13

In the middle of the thoracic cavity is a region occupied by the heart, great vessels, thymus, esophagus, and trachea called the

A) pleural space.

B) pericardial space.

C) mediastinum.

D) cardiac notch.

E) ventral cavity.

C) mediastinum.

14

Contractions of the papillary muscles

A) close the atrioventricular valves.

B) close the semilunar valves.

C) eject blood from the ventricles.

D) prevent the atrioventricular valves from reversing into the atria.

E) eject blood from the atria into the ventricles.

D) prevent the atrioventricular valves from reversing into the atria (the chordae tendineae fibers originate at the papillary muscles)

15

The visceral pericardium is the same as the

A) mediastinum.

B) parietal pericardium.

C) epicardium.

D) myocardium.

E) endocardium.

C) epicardium.

16

The right atrium receives blood from the

A) coronary sinus.

B) superior vena cava.

C) inferior vena cava.

D) systemic circuit.

E) All of the answers are correct.

E) All of the answers are correct.

17

When a blood clot forms on a ruptured plaque in a coronary artery, the condition is referred to as a(n)

A) coronary spasm.

B) myocardial infarction.

C) coronary thrombosis.

D) angina pectoris.

E) pulmonary embolism.

C) coronary thrombosis (clotting)

18

When the left ventricle contracts, the distance from the apex to the base

A) increases.

B) decreases.

C) remains unchanged.

B) decreases.

19

When the left ventricle contracts, the diameter of the ventricular chamber

A) increases.

B) decreases.

C) remains the same.

decreases

20

Cardiac cells damaged by infarction will show which of the following?

A) switch to anaerobic metabolism

B) release of enzymes into the circulation

C) release of troponin T and I into the circulation

D) release of CK-MB into the circulation

E) All of the answers are correct.

E) All of the answers are correct.

21

Blood flowing into the heart from the venae cavae flows next through the ________ valve.

A) mitral

B) bicuspid

C) tricuspid

D) pulmonary semilunar

E) aortic semilunar

C) tricuspid (found between the right atrium and the right vetnricle

22

As blood leaves the right ventricle, it passes through the ________ and then into the pulmonary trunk.

A) pulmonary veins

B) conus arteriosus

C) aorta

D) inferior vena cava

E) superior vena cava

B) conus arteriosus (where the right ventricle tapers before the pulmonary valve)

23

Coronary veins empty into the

A) left atrium.

B) left ventricle.

C) right atrium.

D) right ventricle.

E) conus arteriosus.

C) right atrium (these are the veins bringing dirty blood back from the heart walls to the coronary sulcus)

24

There are ________ pulmonary veins.

A) 2

B) 4

C) 6

D) 8

E) 12

B) 4 (2 left and 2 right pulmonary veins)

25

Rupture of the papillary muscles in the left ventricle may result in

A) mitral regurgitation.

B) mitral valve prolapse.

C) bicuspid regurgitation.

D) bicuspid prolapse.

E) All of the answers are correct.

E) All of the answers are correct (mitral and bicuspid are the same thing; regurgitation is backflow; prolapse is when valves don't close properly and are pushed back into the atria)

26

When the semilunar valves close, the AV valves then

A) close.

B) open.

C) make the third heart sound.

D) contract.

E) prolapse.

B) open.

27

The ________ deliver(s) blood to the myocardium.

A) coronary arteries

B) cardiac veins

C) superior vena cava

D) carotid arteries

E) coronary sinus

A) coronary arteries (in systemic circuit arteries have clean blood moving away from heart, veins have dirty blood moving towards the heart)

28

The connective tissue fibers of the myocardium

A) add strength and prevent overexpansion of the heart.

B) help distribute the forces of contraction.

C) provide elasticity to help return the heart to its normal size.

D) provide physical support for cardiac muscle.

E) All of the answers are correct.

E) All of the answers are correct (myocardium is muscular tissue of the heart)

29

Blood is supplied to the muscular wall of the left atrium by the

A) brachiocephalic artery.

B) right coronary artery.

C) left coronary artery.

D) phrenic arteries.

E) pulmonary arteries.

C) left coronary artery (supplies blood to the left ventricle, left atrium, and interventricular septum)

30

The pulmonary semilunar valve prevents backward flow into the

A) aorta.

B) pulmonary trunk.

C) pulmonary veins.

D) right ventricle.

E) left atrium.

D) right ventricle (in between the right ventricle and the pulmonary trunk)

31

The bicuspid or mitral valve is located

A) in the opening of the aorta.

B) in the opening of the pulmonary trunk.

C) where the venae cavae join the right atrium.

D) between the right atrium and right ventricle.

E) between the left atrium and left ventricle.

E) between the left atrium and left ventricle.

32

The ________ valve prevents backward flow into the left atrium.

A) semicaval

B) semilunar

C) bicuspid

D) tricuspid

E) pulmonic

C) bicuspid (left atrioventricular valve)

33

The function of an atrium is to

A) collect blood.

B) pump blood to the lungs.

C) pump blood into the systemic circuit.

D) pump blood to the ventricle.

E) collect blood then pump it to the ventricle.

E) collect blood then pump it to the ventricle.

34

Compared to the right ventricle, the left ventricle has all the following characteristics except

A) has a thicker wall.

B) is round in cross section.

C) pumps a greater volume.

D) works harder.

E) produces about four to six times more pressure when it contracts.

C) pumps a greater volume (ventricles hold and pump equal amounts of blood)

35

Which of the following are involved in the pulmonary circuit?

A) superior vena cava, right atrium, left ventricle

B) right ventricle, pulmonary veins, aorta

C) right ventricle, pulmonary trunk, left atrium

D) inferior vena cava, right atrium, aorta

E) left ventricle, pulmonary veins, right atrium

C) right ventricle, pulmonary trunk, left atrium

36

The right pulmonary veins carry ________ blood to the ________.

A) deoxygenated; left atrium

B) oxygenated; right lung

C) deoxygenated; superior vena cava

D) deoxygenated; right atrium

E) oxygenated; left atrium

E) oxygenated; left atrium

37

The following is a list of vessels and structures that are associated with the heart. What is the correct order for the flow of blood entering from the systemic circulation?

  1. right atrium
  2. left atrium
  3. right ventricle
  4. left ventricle
  5. venae cavae
  6. aorta
  7. pulmonary trunk
  8. pulmonary veins

A) 1, 2, 7, 8, 3, 4, 6, 5

B) 1, 7, 3, 8, 2, 4, 6, 5

C) 5, 1, 3, 7, 8, 2, 4, 6

D) 5, 3, 1, 7, 8, 4, 2, 6

E) 5, 1, 3, 8, 7, 2, 4, 6

C) 5, 1, 3, 7, 8, 2, 4, 6

38

The pulmonary arteries carry blood to the

A) heart.

B) lungs.

C) brain.

D) intestines.

E) liver.

B) lungs.

39

The pulmonary veins carry blood to the

A) heart.

B) lungs.

C) brain.

D) intestines.

E) liver.

A) heart.

40

The foramen ovale in the fetal heart is located in the

A) right atrium.

B) left atrium.

C) right ventricle.

D) left ventricle.

E) interatrial septum.

E) interatrial septum (because the foramen ovale connected the 2 atrium in the fetus, therefore has to be in the septum not the atrium)

41

Blood is supplied to the myocardium by

A) the coronary sinus.

B) contact with blood in the pumping chambers.

C) the coronary arteries.

D) arteries that branch from the pulmonary arteries.

E) arteries that branch off the subclavian arteries.

C) the coronary arteries (to feed to heart walls oxygenated blood)

42

The first blood vessels to branch from the aorta are the ________ arteries.

A) pulmonary

B) coronary

C) circumflex

D) carotid

E) subclavian

B) coronary (feeds itself first)

43

The marginal branch and posterior interventricular branch are branches of the

A) right coronary artery.

B) left coronary artery.

C) circumflex artery.

D) coronary sinus.

E) aorta.

A) right coronary artery.

44

The circumflex branch and the anterior interventricular artery are branches of the

A) right coronary artery.

B) left coronary artery.

C) interventricular artery.

D) coronary sinus.

E) aorta.

B) left coronary artery.

45

The great and middle cardiac veins drain blood into the

A) superior vena cava.

B) inferior vena cava.

C) coronary sinus.

D) coronary sulcus.

E) aorta.

C) coronary sinus.

46

In cardiac muscle, the fast depolarization phase of the action potential is the result of

A) increased membrane permeability to sodium ions.

B) increased membrane permeability to potassium ions.

C) decreased membrane permeability to calcium ions.

D) decreased membrane permeability to sodium ions.

E) increased membrane permeability to chloride ions.

A) increased membrane permeability to sodium ions.

47

The long plateau phase of the cardiac muscle action potential is due to

A) movement of fewer sodium ions across the cell membrane.

B) calcium channels remaining open.

C) increased membrane permeability to potassium ion.

D) decrease in the amount of calcium diffusing across the membrane.

E) increased membrane permeability to sodium ions.

B) calcium channels remaining open (calcium coming in)

48

In cardiac muscle

A) calcium ions are not released from the sarcoplasmic reticulum.

B) calcium ions do not bind to troponin molecules.

C) calcium ions play no role in the process of contraction.

D) about 20 percent of the calcium ion required for contraction comes from outside the cell.

E) calcium ions play an important role in repolarizing the membrane after the depolarization phase.

D) about 20 percent of the calcium ion required for contraction comes from outside the cell.

49

The normal pacemaker of the heart is located in

A) the Purkinje fibers.

B) the sinoatrial node.

C) the atrioventricular node.

D) the wall of the left ventricle.

E) both the left and right ventricles.

B) the sinoatrial node.

50

Abnormally slow depolarization of the ventricles would most change the shape of the ________ in an ECG tracing.

A) P wave

B) T wave

C) QRS complex

D) P-R interval

E) R-T interval

C) QRS complex

51

As a result of the long refractory period in the cardiac action potential, cardiac muscle cannot exhibit

A) tonus.

B) treppe.

C) tetany.

D) recruitment.

E) fatigue.

C) tetany (tetany is spasms or cramps; refractory period is time it takes for muscle to respond to second stimulus/action potential)

52

If the pacemaker cells in the SA node become more permeable to potassium ions, the

A) heart rate will increase.

B) heart rate will decrease.

C) cells will depolarize.

D) cells will hyperpolarize.

E) heart rate will decrease and cells will hyperpolarize.

D) cells will hyperpolarize (K+/potassium causes hyperpolarization)

53

If the connection between the SA node and AV node becomes blocked,

A) the ventricles will beat faster.

B) the ventricles will beat more slowly.

C) the ventricular beat will remain unchanged.

D) cardiac output will increase.

E) the atria will contract more forcefully.

B) the ventricles will beat more slowly (electrical cannot get through to stimulate the ventricles to contract)

54

The following are structural components of the conducting system of the heart.

  1. Purkinje fibers
  2. AV bundle
  3. AV node
  4. SA node
  5. bundle branches

The sequence in which excitation would move through this system is

A) 1, 4, 3, 2, 5.

B) 3, 2, 4, 5, 1.

C) 3, 5, 4, 2, 1.

D) 4, 3, 2, 5, 1.

E) 4, 2, 3, 5, 1.

D) 4, 3, 2, 5, 1.

55

The P wave of the electrocardiogram is a signal from

A) the SA node.

B) depolarization of the AV node.

C) depolarization of the atria.

D) repolarization of the atria.

E) depolarization of the ventricles.

C) depolarization of the atria.

56

If there is a complete block between the SA node and the AV node, how would the ECG be affected?

A) The P-R interval will be shorter.

B) The QRS duration will be longer.

C) There will be much bigger P waves.

D) The ventricles will stop beating.

E) The rate of P waves will be faster than the rate of QRS complexes.

E) The rate of P waves will be faster than the rate of QRS complexes.

57

Depolarization of the ventricles is represented on an electrocardiogram by the

A) P wave.

B) T wave.

C) S wave.

D) QRS complex.

E) PR complex.

D) QRS complex.

58

The T wave on an ECG tracing represents

A) atrial depolarization.

B) atrial repolarization.

C) ventricular depolarization.

D) ventricular repolarization.

E) ventricular contraction.

D) ventricular repolarization.

59

Analysis of the electrocardiogram can reveal all of the following except

A) heart rate.

B) stroke volume.

C) the condition of the conducting system.

D) the effects of drugs and poisons.

E) the duration of the ventricular action potential.

B) stroke volume (amount of blood ejected from the ventricles)

60

During the T wave of the electrocardiogram, the ventricles are

A) depolarizing.

B) repolarizing.

C) contracting.

D) relaxing.

E) both repolarizing and relaxing.

E) both repolarizing and relaxing.

61

Pacemaker cells in the SA node

A) have a well-defined resting potential.

B) can spontaneously depolarize.

C) also contract with the rest of the cells in the heart wall.

D) are special neurons that convey signals from the brain to the heart.

E) All of the answers are correct.

B) can spontaneously depolarize.

62

Pacemaker cells isolated from the SA node generate action potentials at ________ beats per minute.

A) 20-40

B) 40-60

C) 80-100

D) 100-140

E) 140-180

C) 80-100

63

Depolarization of the atria corresponds to the EKG's

A) P wave.

B) QRS complex.

C) QT interval.

D) T wave.

E) S-T segment.

A) P wave.

64

The first heart sound is heard when the

A) AV valves open.

B) AV valves close.

C) semilunar valves close.

D) atria contract.

E) blood enters the aorta.

B) AV valves close ("lubb" when mitral and tricuspid valves close)

65

The first heart sound ("lubb") is associated with

A) atrial systole.

B) closing of the atrioventricular valves.

C) opening of the atrioventricular valves.

D) closing of the semilunar valves.

E) opening of the semilunar valves.

B) closing of the atrioventricular valves (tricuspid/mitral valves)

66

Considering the left ventricle, why does isovolumetric ventricular contraction occur during ventricular systole?

A) The ventricle needs to pressurize the blood to close the aortic valve.

B) Ventricular pressure is greater than atrial pressure so the ventricle cannot eject blood.

C) The bicuspid valve needs time to shut before the ventricle can eject blood.

D) Aortic pressure is higher than ventricular pressure and the ventricle must pressurize the blood to open the aortic valve.

E) The ventricle is still filling with blood and therefore cannot eject blood during this time.

D) Aortic pressure is higher than ventricular pressure and the ventricle must pressurize the blood to open the aortic valve (even though the ventricles contract they do not eject blood; all valves closed; pressure in pulmonary trunk and atria is still greater)

67

The phase in the cardiac cycle when the mitral valve is closed and the aortic valve is open is the

A) atrial systole.

B) early diastolic filling phase.

C) late diastolic filling phase.

D) systolic ejection phase.

E) dicrotic phase.

D) systolic ejection phase.

68

A heart murmur might be caused by

A) aortic valve insufficiency.

B) mitral valve insufficiency.

C) pulmonic valve insufficiency.

D) swirling of blood in the ventricle.

E) All of the answers are correct.

E) All of the answers are correct.

69

At a heart rate of 60 beats/minute, a cardiac cycle lasts

A) 60 seconds.

B) 60 milliseconds.

C) 1 second.

D) 370 milliseconds.

E) 630 milliseconds.

C) 1 second.

70

During ventricular systole, the

A) atria are contracting.

B) blood is entering the ventricles.

C) AV valves are closed.

D) pressure in the ventricles remains constant.

E) pressure in the aorta remains constant.

C) AV valves are closed.

71

With each ventricular systole,

A) blood pressure remains steady.

B) the ventricles fill with blood.

C) blood pressure decreases.

D) cardiac output decreases.

E) blood pressure increases.

E) blood pressure increases.

72

An increase in the rate of action potentials from baroreceptors will trigger a reflex to

A) increase heart rate.

B) decrease heart rate.

C) decrease blood pressure.

D) both decrease heart rate and decrease pressure.

E) both increase heart rate and increase pressure.

D) both decrease heart rate and decrease pressure.

73

The volume of blood ejected from each ventricle during a contraction is called the

A) end-diastolic volume.

B) end-systolic volume.

C) stroke volume.

D) cardiac output.

E) cardiac reserve.

C) stroke volume.

74

Each of the following factors will increase cardiac output except increased

A) venous return.

B) parasympathetic stimulation.

C) sympathetic stimulation.

D) heart rate.

E) force of contraction.

B) parasympathetic stimulation.

75

"An increase in end-diastolic volume increases the stroke volume" is a way of stating ________ law of the heart.

A) Robin's

B) Finch's

C) Starling's

D) Sparrow's

E) Hawking's

C) Starling's

76

Which of the following would increase heart rate?

A) increased sympathetic stimulation of SA node

B) decreased parasympathetic stimulation of nodal fibers

C) increased levels of epinephrine

D) faster depolarization of the pacemaker potential

E) All of the answers are correct.

E) All of the answers are correct.

77

The heart is innervated by ________ nerves.

A) parasympathetic

B) sympathetic

C) both parasympathetic and sympathetic

D) neither parasympathetic nor sympathetic

E) somatomotor

C) both parasympathetic and sympathetic (in the cardiac plexus)

78

Stroke volume depends on

A) end diastolic volume.

B) the contractility of the ventricle.

C) the pressure required to pump blood into the aorta.

D) venous return of blood to the heart.

E) All of the answers are correct.

E) All of the answers are correct.

79

Cardiac output can be increased by all of the following except

A) decreasing ejection fraction.

B) decreasing end systolic volume.

C) increasing stroke volume.

D) increasing ejection fraction.

E) increasing heart rate.

A) decreasing ejection fraction.

80

Drugs known as calcium channel blockers such as nifedipine can be used to

A) decrease the force of cardiac contraction.

B) decrease blood pressure.

C) dilate the coronary arteries.

D) produce a negative inotropic effect.

E) All of the answers are correct.

E) All of the answers are correct.

81

Heart rate is controlled by neurons of the cardiovascular center located in the

A) pons.

B) thalamus.

C) medulla oblongata.

D) hypothalamus.

E) higher centers.

medulla oblongata.

82

The cardioacceleratory center activates sympathetic neurons and the cardioinhibitory center controls parasympathetic neurons.

A) The first part of the statement is true but the second part is false.

B) The first part of the statement is false but the second part is true.

C) Both parts of the statement are true.

D) Both parts of the statement are false.

E) The first part is always true, but the second part is sometimes true.

C) Both parts of the statement are true.

83

Which of the following is true about the atrial reflex?

A) also called Bainbridge reflex

B) triggered by atrial stretch receptors

C) triggered by increasing venous return

D) depends on sympathetic innervation

E) All of the answers are correct.

E) All of the answers are correct.

84

Which of the following would cause stroke volume to increase?

A) when venous return is decreased

B) when ventricular contraction is reduced

C) when diastolic blood pressure is decreased

D) decrease in heart rate

E) All of the answers are correct.

C) when diastolic blood pressure is decreased

85

Cardiac output is increased by

A) sympathetic stimulation.

B) increased end systolic volume.

C) decreased end diastolic volume.

D) decreased venous return.

E) inhibiting the atrial reflex.

A) sympathetic stimulation.

86

Activation of which kind of receptor causes heart rate to increase?

A) alpha-one

B) beta-one

C) muscarinic

D) beta-two

E) preganglionic

B) beta-one

87

Drugs that block the beta-one adrenergic receptors will

A) increase heart rate.

B) decrease heart rate.

C) increase contractility.

D) increase cardiac output.

E) decrease the end-systolic volume.

B) decrease heart rate.

88

If the force of ventricular contraction increases, what will happen to the end-systolic volume?

A) increase

B) fluctuate rapidly

C) remain the same

D) decrease

E) reduced to zero

D) decrease (ventricle won't have chance to fill as much)

89

End-systolic volume is defined as the

A) amount of blood a ventricle ejects per cycle.

B) amount of blood which backflows into a ventricle.

C) amount of blood remaining in an atrium after atrial systole.

D) amount of blood remaining in a ventricle after contraction.

E) stroke volume multiplied by the heart rate.

D) amount of blood remaining in a ventricle after contraction.

90

A patient has an end-diastolic volume of 125 ml. A heart attack has weakened her left ventricle so it can pump a stroke volume of only 40 ml. Calculate her end-systolic volume.

A) 85 ml

B) 3.1 ml

C) 5000 ml

D) 165 ml

E) There is not enough data given to calculate the end-systolic volume.

A) 85 ml (SV = EDV - ESV or 40 = 125 - x)

91

Calculate cardiac output if the heart rate is 125 beats/minute, the end-diastolic volume is 130 ml, and the end-systolic volume is 40 ml.

A) 21,250 ml / min

B) 16,250 ml / min

C) 11,250 ml / min

D) 195 ml / min

E) 200 ml / min

C) 11,250 ml / min (CO = HR x SV or 125 x 90 = 11250)

92

Calculate the cardiac output of a patient with a heart rate of 100 beats/minute and a stroke volume of 75 ml.

A) 0.75 ml / min

B) 750 ml / min

C) 7500 ml / min

D) 175 ml / min

E) 25 ml / min

C) 7500 ml / min (CO = HR x SV)

93

The heart lies within the ________ cavity.

A) peritoneal

B) pleural

C) orbital

D) dorsal

E) pericardial

E) pericardial

94

The superior portion of the heart where major blood vessels enter and exit is the

A) apex.

B) hilum.

C) base.

D) septum.

E) mediastinum.

C) base.

95

The inferior point of the heart is called the

A) apex.

B) hilum.

C) base.

D) septum.

E) mediastinum.

A) apex.

96

Most of the mass of the heart lies

A) left of midline.

B) right of midline.

C) on the sagittal plane.

D) inferior to the midline.

E) on the midline of the body.

A) left of midline.

97

The wall of the ________ rests on the diaphragm.

A) left atrium

B) right ventricle

C) left ventricle

D) right atrium

E) aorta

B) right ventricle

98

The space between the pleural cavities is called the

A) mediastinum.

B) subcardium.

C) endocardium.

D) myocardium.

E) epicardium.

A) mediastinum.

99

Pericardial fluid

A) provides oxygen to the heart muscle.

B) is located between the myocardium and the endocardium.

C) is a lubricant between the heart and the pericardial sac.

D) consists of plasma that has leaked out of whole blood.

E) flows through the four chambers of the heart.

C) is a lubricant between the heart and the pericardial sac.

100

The ________ is shared by the two ventricles.

A) vena cava

B) bicuspid valve

C) chordate tendinae

D) interventricular septum

E) trabeculae

D) interventricular septum

101

Muscular ridges on the inner surface of the ventricles are called

A) coronary sinuses.

B) trabeculae carneae.

C) intercalated discs.

D) papillary muscles.

E) chordate tendinae.

B) trabeculae carneae.

102

The ________ circuit carries blood to and from the lungs.

A) pulmonary

B) systemic

C) oxygen

D) portal

E) body

A) pulmonary

103

The ________ circuit carries blood from the aorta to the right ventricle.

A) pulmonary

B) systemic

C) oxygen

D) portal

E) body

B) systemic

104

The ________ carry blood away from the heart.

A) arterioles

B) arteries

C) veins

D) venules

E) capillaries

B) arteries

105

The ________ carry blood toward the heart.

A) arterioles

B) arteries

C) veins

D) lacteals

E) capillaries

C) veins

106

The ________ covers the outer surface of the heart.

A) epicardium

B) myocardium

C) endocardium

D) parietal pericardium

E) mediastinum

A) epicardium

107

The muscle layer of the heart is the

A) epicardium.

B) myocardium.

C) endocardium.

D) parietal pericardium.

E) mediastinum.

B) myocardium.

108

The ________ lines the chambers of the heart, covers the heart valves, and is continuous with the endothelium.

A) epicardium

B) myocardium

C) endocardium

D) visceral pericardium

E) mediastinum

C) endocardium

109

Oxygen is added to blood as it flows through the ________ circuit.

A) pulmonary

B) systemic

C) oxygen

D) portal

E) body

A) pulmonary

110

The term ________ refers to blockage in the coronary circulation.

A) congestive heart failure

B) atherosclerosis

C) coronary artery disease

D) embolism

E) phlebitis

C) coronary artery disease

111

________ is the symptom generally brought on by coronary ischemia.

A) Angina pectoris

B) Shortness of breath

C) A rash

D) Hematuria

E) Fluid in the lungs

A) Angina pectoris (chest pain caused by reduced blood flow to the heart) (ischemia is inadequate blood supply)

112

In a procedure known as ________, an inflatable balloon at the end of a catheter is used to press plaque back against the vessel wall.

A) balloon angioplasty

B) coronary arterial bypass graft

C) intravenous catheterization

D) ablation

E) atherectomy

A) balloon angioplasty

113

A procedure in which a length of the patient's vein or artery is used to create a detour around an obstruction in a coronary artery is called

A) balloon angioplasty.

B) coronary arterial bypass graft.

C) intravenous catheterization.

D) ablation.

E) atherectomy

B) coronary arterial bypass graft.

114

Which of the following statements is true regarding cardiac muscle?

A) Its main source of ATP production is glycogen.

B) The actin and myosin myofilaments are not arranged in sarcomeres.

C) Cardiac muscle preferentially metabolizes anaerobically.

D) There are specialized gap junctions in cardiac muscle not found in skeletal or smooth muscles.

E) Cardiac muscle goes into sustained contractions faster than skeletal muscle.

D) There are specialized gap junctions in cardiac muscle not found in skeletal or smooth muscles.

115

A fine tubular wire mesh called a ________ may be inserted into a coronary vessel, holding it open.

A) angioplast

B) stent

C) angiogram

D) keyhole

E) catheter

B) stent

116

The coronary sinus drains the ________ into the ________

A) coronary arteries; left ventricle

B) cardiac veins; right atrium

C) interventricular artery; left ventricle

D) right atrium; right ventricle

E) cardiac vein; right ventricle

.

B) cardiac veins; right atrium

117

The ________ is a remnant of an important fetal blood vessel that once linked the pulmonary and systemic circuits.

A) fossa ovalis

B) ductus arteriosus

C) foramen ovale

D) ductus venosus

E) ligamentum arteriosum

E) ligamentum arteriosum

118

Which of the following statements is true concerning differences between the right and left ventricles?

A) The right ventricle pumps with more force compared to the left.

B) The left ventricles pumps twice as much blood as the right ventricle.

C) The right ventricles pumps blood to the body, whereas the left ventricle pumps blood to the lungs.

D) The right ventricle is conical-shaped while the left ventricle is half-moon shaped.

E) The efficiency of the right ventricle is increased by the left ventricle because the wall of the left ventricle pushes into the right ventricle.

E) The efficiency of the right ventricle is increased by the left ventricle because the wall of the left ventricle pushes into the right ventricle.

119

The two types of cardiac muscle cells involved in a normal heartbeat include specialized cells of the conducting system and ________ cells.

A) contractile

B) conductive

C) intercalated

D) pacemaker

E) internodal

A) contractile

120

The property of heart muscle to contract in the absence of neural or hormonal stimulation is called

A) intrinsic.

B) extrinsic.

C) automaticity.

D) self-replicating.

E) self-starting.

C) automaticity (or autorhythmicity)

121

Cells that spontaneously make action potentials make up ________ tissue.

A) contractile

B) conductive

C) intercalated

D) pacemaker

E) internodal

D) pacemaker

122

The structures responsible for distributing excitation to the contractile cells are

A) contractile cells.

B) conducting cells.

C) intercalated cells.

D) pacemaker cells.

E) intermodal cells.

B) conducting cells.

123

The contraction phase of the cardiac cycle is called

A) depolarization.

B) systole.

C) diastole.

D) hyperpolarization.

E) asystole.

B) systole.

124

The relaxation phase of the cardiac cycle is called

A) depolarization.

B) systole.

C) diastole.

D) hyperpolarization.

E) asystole.

C) diastole.

125

Which event occurs during ventricular systole?

A) closing of the bicuspid and tricuspid valves

B) closing of the semilunar valves

C) the second heart sound

D) release of an action potential from the sinoatrial node

E) expansion of the ventricles

A) closing of the bicuspid and tricuspid valves

126

Abnormal heart sounds caused by turbulent flow through faulty valves are called

A) ectopic foci.

B) murmurs.

C) asystole.

D) fibrillations.

E) flutters.

B) murmurs.

127

The backward flow of blood from a ventricle to its atrium or from a outflow vessel to its ventricle is called

A) emesis.

B) flutter.

C) fibrillation.

D) regurgitation.

E) stenosis.

D) regurgitation.

128

In mitral valve prolapse, the cusps of the mitral valve are pushed into the

A) left ventricle.

B) right ventricle.

C) left atrium.

D) right atrium.

C) left atrium.

129

The ________ is the amount of blood in a ventricle after it has contracted and before it begins to refill.

A) ejection fraction

B) end-diastole volume

C) start-diastolic volume

D) end-systolic volume

E) stroke volume

D) end-systolic volume

130

The ________ is the volume of blood in a ventricle at the beginning of systole.

A) ejection fraction

B) end-diastole volume

C) start-diastolic volume

D) end-systolic volume

E) stroke volume

B) end-diastole volume

131

The amount of blood remaining in the ventricle when the semilunar valve closes is the

A) ejection fraction.

B) end-diastole volume.

C) start-diastolic volume.

D) end-systolic volume.

E) stroke volume.

D) end-systolic volume.

132

________ is when the heart can't maintain adequate cardiac output.

A) Heart failure

B) Fibrillation

C) Flutter

D) Murmur

E) Coronary heart disease

A) Heart failure

133

The ________ is the difference between the resting and maximal cardiac output.

A) end-systolic volume

B) end-diastolic volume

C) cardiac reserve

D) stroke volume

E) ejection fraction

C) cardiac reserve

134

The principle that increasing the end-diastolic volume results in a corresponding increase in the stroke volume is known as

A) afterload.

B) cardiac capacity.

C) cardiac reserve.

D) Starling's law of the heart.

E) expandibility.

Starling's law of the heart.

135

The amount of blood returning to the heart is the

A) afterload.

B) stroke volume.

C) end-diastolic volume.

D) cardiac reserve.

E) venous return.

venous return

136

A doctor tells her nursing students that it is important to monitor patients' blood pressure when they are receiving verapamil (a calcium channel blocker). Why?

Calcium channel blockers inhibit the movement of calcium ions from the interstitial fluid into cardiac and smooth muscle cells. This would cause a decrease in heart rate, stroke volume, and cardiac output. These in turn would lower blood pressure. In addition, the calcium channel blockers would also inhibit contraction of the smooth muscle in the wall of blood vessels, causing them to get wider and thus also lower blood pressure. Because both heart and smooth muscle cells are inhibited by verapamil, its effects on blood pressure are particularly potent.

137

A patient's ECG recording shows a very long P-R interval. What is the cause of this abnormal wave pattern?

The P wave marks the time of atrial depolarization and the QRS complex signals ventricular depolarization. Between those two events the AV node was excited and the action potential was spread through the conducting tissue to the ventricular myocardium. A prolonged P-R interval signifies an usually slow conduction through the AV node and conducting system, possibly due to insufficient blood flow (ischemia).

138

If a patient's resting cardiac output is 5.6 l/min and on a stress test she elevated her heart rate to a maximum of 176 beats/min with a stroke volume of 115 ml/beat, what is her cardiac reserve? Show your work.

Cardiac reserve equals maximum cardiac output - resting cardiac output. Maximum CO = HR × SV = 176 beats/minute × 0.115 liters/beat = 20.2 liters/minute. Cardiac reserve equals 14.6 liters/minute.

139

Which of the following contains the trabeculae carneae?

  1. Pericardial sac
  2. Pulmonary trunk
  3. Right atrium
  4. Right ventricle

right ventricle

140

Blood flows from the left atrium through the __________ to the left ventricle.

  1. tricuspid valve
  2. mitral valve
  3. aortic valve
  4. pulmonary valve

mitral valve (also known as left atrioventricular (AV) valve or biscuspid)

141

The left coronary artery supplies blood to __________.

  1. the anterior interventricular artery and the circumflex branch
  2. the anterior interventricular artery
  3. the posterior descending artery
  4. the circumflex branch

the anterior interventricular artery and the circumflex branch

142

Which of the following is NOT a characteristic of cardiac muscle cells?

  1. They have short T tubules.
  2. Calcium entry is a trigger for contraction.
  3. They have multiple nuclei.
  4. Mitochondria account for 25 percent of cell volume.

They have multiple nuclei.

143

Which heart chamber has the thickest muscular walls?

  1. Reft atrium
  2. Right atrium
  3. Right ventricle
  4. Left ventricle

D) Left ventricle

144

Which vessels have very thin walls and are often called exchange vessels because they allow for the exchange of nutrients, gases, and wastes with surrounding tissues?

  1. Ventricles
  2. Veins
  3. Arteries
  4. Capillaries

D. Capillaries

145

What is the function of the chordae tendineae?

  1. To anchor the AV valve flaps and prevent backflow of blood into the atria
  2. To anchor the aortic valve flaps and prevent backflow into the ventricles
  3. To anchor the bicuspid valve flaps and prevent backflow of blood into the ventricles
  4. To anchor the semilunar valve flaps and prevent backward flow of blood into the ventricles

A. To anchor the AV valve flaps and prevent backflow (regurgitation) of blood into the atria

146

Which valve is found between the right atrium and the right ventricle?

  1. Tricuspid
  2. Bicuspid or mitral
  3. Pulmonary
  4. Aortic

A. Tricuspid

147

The passageways between cardiac muscle cells that allow ions to pass freely are called __________.

  1. gap junctions
  2. trabeculae carneae
  3. anastomoses
  4. desmosomes

A. Gap junctions

148

The “double pump” function of the heart includes the right side, which serves as the __________ circuit pump, and the left side, which serves as the __________ pump.

  1. pulmonary; systemic
  2. systemic; pulmonary
  3. hepatic portal; cardiac
  4. pulmonary; hepatic portal

A. pulmonary; systemic

149

The right and left coronary arteries originate at the base of the __________.

  1. ascending aorta
  2. superior vena cava
  3. pulmonary veins
  4. pulmonary trunk

A. ascending aorta

150

The blood vessels in the cardiovascular system are subdivided into three circuits known as the __________.

  1. coronary, pulmonary, and systemic circuits
  2. pulmonary, venous, and systemic circuits
  3. lymphatic, pulmonary, and systemic circuits
  4. pulmonary, systemic, and arterial circuits

A. coronary, pulmonary, and systemic circuits

151

A large vein that opens into the right atrium and brings in venous blood from the heart tissue is the __________.

  1. coronary sinus
  2. arterial anastomoses
  3. posterior cardiac vein
  4. marginal artery

A. coronary sinus

152

Valvular heart disease can be a result of __________.

  1. congenital malformation, carditis, or rheumatic fever
  2. congenital malformation
  3. rheumatic fever
  4. carditis

A. congenital malformation, carditis, rheumatic fever

153

When deoxygenated blood leaves the right ventricle through a semilunar valve, it is forced into the __________.

  1. pulmonary arteries
  2. lung capillaries
  3. pulmonary veins
  4. aortic arch

A. pulmonary arteries

154

The left atrium receives blood from the pulmonary circuit and empties it into the __________.

  1. right ventricle
  2. conus arteriosus
  3. left ventricle
  4. right atrium

C. left ventricle

155

The plateau of the action potential in cardiac muscle cells is due to __________.

  1. Ca2+ entry into the cells
  2. Ca2+ exiting from the cardiac muscle cells
  3. K+ exiting from the cardiac muscle cells
  4. Na+ entry into the cardiac muscle cells

A. Calcium (Ca2) entry into the cells

156

Which of the following occurs during the first phase of ventricular systole?

  1. The AV valves open, and blood flows into the ventricles.
  2. The semilunar valves open, and blood is pushed into the aorta and pulmonary trunk.
  3. The atria contract, and ventricular pressure rises.
  4. The AV valves close, and ventricular pressure rises.

D. The AV valves close, and ventricular pressure rises.

157

What is happening during isovolumetric contraction?

  1. No blood is being ejected from the ventricles.
  2. The same volume of blood is ejected from both ventricles.
  3. During a short sequence of ventricular contractions, the same volume of blood is ejected with each beat.
  4. The ventricles are fill with the same volume of blood.

A. No blood is being ejected from the ventricles

158

When do the semilunar valves close?

  1. When the QRS wave occurs
  2. When the muscle in them is stimulated to contract by the conduction system
  3. When the pressure in the arteries is greater than the pressure in the ventricles
  4. When the P wave occurs

C. When the pressure in the arteries is greater than the pressure in the ventricles

159

During ventricular systole, the blood volume in the atria is __________, and the volume in the ventricle is __________.

  1. decreasing; decreasing
  2. increasing; decreasing
  3. increasing; increasing
  4. decreasing; increasing

B. increasing; decreasing

160

If cells of the SA node did NOT function, what would happen to the heart?

  1. The heart would beat more slowly.
  2. The heart would stop.
  3. The heart rate would increase.
  4. The ventricle would take over as the pacemaker.

A. The heart would beat more slowly

161

What has its own intrinsic conduction system to set the pace of the beating heart?

Cardiac muscle tissue

162

Decreased parasympathetic (vagus) stimulation to the heart results in a situation known as __________.

  1. tachycardia
  2. carditis
  3. stenosis
  4. bradycardia

A. tachycardia (fast)

163

Which of the following are characteristics of cardiac muscle cells?

  1. Striated, single central nucleus, and involuntary
  2. Nonstriated, multinucleated, and involuntary
  3. Striated, multinucleated, and voluntary
  4. Striated, single central nucleus, and voluntary

A. Striated, single central nucleus, and involuntary

164

When a chamber of the heart fills with blood and prepares for the start of the next cardiac cycle, the chamber is in __________.

  1. systole
  2. isovolumetric contraction
  3. diastole
  4. ventricular ejection

C. diastole

165

How do the SA node cells cause autorhythmicity?

  1. They have a slow inflow of Na+ after repolarization.
  2. They are very sensitive to autonomic stimulation.
  3. They leak K+ out.
  4. Ca2+ enters from the extracellular fluid spontaneously.

A. They have a slow inflow of Na+ (sodium) after repolarization.

166

What is the name of the volume of blood in the ventricles immediately before they contract?

  1. End-systolic volume
  2. End-diastolic volume
  3. Stroke volume
  4. Ventricular ejection volume

B. End-diastolic volume

167

Why is it important for impulses from the atria to be delayed at the AV node before they pass into the ventricles?

  1. So the atria can relax before the ventricles contract
  2. So the ventricles can finish filling
  3. So the AV valves can close before the ventricles contract
  4. So the AV bundle can receive the stimulus

B. So the ventricles can finish filling

168

What structures in the conduction system conduct impulses very rapidly to the ventricular myocardium?

  1. Purkinje fibers
  2. SA node
  3. AV bundle branches
  4. AV bundle

A. Purkinje fibers

169

The QRS complex of the ECG appears as the __________.

  1. ventricles repolarize
  2. atria depolarize
  3. ventricles depolarize
  4. atria repolarize

C. ventricles depolarize

170

The first sound of the heart occurs as a result of __________.

  1. the QRS Complex
  2. contraction of the atria
  3. the T wave
  4. the P wave

A. QRS complex

171

Which of the following events does NOT occur because of the QRS wave?

  1. Semilunar valves open
  2. The pressure in ventricles rises.
  3. Blood is ejected out of the ventricles.
  4. The AV valves open..

D. The AV valve opens

172

What ion movement is responsible for the rapid depolarization phase of the ventricular muscle cell action potential?

  1. Na+ inflow
  2. Ca2+ inflow
  3. K+ inflow
  4. K+ outflow

A. Na+ (sodium) inflow

173

Physicians are interested in cardiac output because it provides a useful indication of __________.

  1. the amount of blood ejected by each ventricle
  2. ventricular efficiency over time
  3. atrial efficiency in respect to time
  4. valvular malfunctions

B. ventricular efficiency over time

174

What part of the brain controls cardiac function?

  1. The medulla oblongata
  2. The cerebral cortex
  3. The cerebellum
  4. The pons

A. medulla oblongata

175

What is happening during the atrial reflex?

  1. The atria increase contractility.
  2. The atria relax to accommodate more blood.
  3. The heart rate increases.
  4. The heart rate decreases.

C. The heart rate increases

176

Parasympathetic stimulation from the vagus nerve results in __________.

  1. more forceful ventricular contractions
  2. no effect on the heart rate
  3. an increased heart rate and cardiac output
  4. a decrease in heart rate

D. a decrease in heart rate

177

What is the potential problem if the heart beats too rapidly?

  1. Filling time decreases.
  2. Cardiac output increases too much.
  3. The heart has to work too hard.
  4. Blood pressure increases too much.

A. filling time decreases

178

How should you define cardiac output?

  1. The end-diastolic volume plus the end-systolic volume
  2. The amount of blood pumped out of the left ventricle in one minute
  3. The amount of blood pumped out of the atria and the ventricles in one minute
  4. The amount of blood pumped out of both ventricles in one minute

B. The amount of blood pumped out of the left ventricle in one minute

179

Which statement is NOT a component of the Frank-Starling Principle?

  1. “More in = more out”
  2. Increasing end-diastolic volume increases stroke volume.
  3. Stretching heart muscle increases contractility.
  4. Slowing the heart rate decreases stroke volume.

D. Slowing the heart rate decreases stroke volume

180

Which of the following could increase the strength of the contraction of a ventricle?

  1. Increased stretch on the ventricle
  2. Negative inotropic drugs, such as beta-blockers
  3. Lower venous return
  4. Parasympathetic stimulation

A. increased stretch on the ventricle

181

Cardiac reflexes that adjust cardiac function are triggered by sensory input to the cardiac centers. Which sensory information is NOT something that triggers these reflexes?

  1. Blood pressure
  2. Heart rate
  3. Carbon dioxide concentrations in the blood
  4. Oxygen concentrations in the blood

B. Heart rate

182

Which of the following statements about autonomic tone is FALSE?

  1. ACh and NE are released at the nodes.
  2. Resting heart rate is 70–80 beats per minute.
  3. Sympathetic effects dominate in a resting healthy adult.
  4. Parasympathetic rates dominate in a resting healthy adult.

C. Sympathetic effects dominate in a resting healthy adult.

183

How does sympathetic stimulation increase the heart rate?

  1. Increasing Na+ outflow out of SA node cells
  2. Increasing K+ inflow into SA node cells
  3. Increasing Ca2+ outflow out of SA node cells
  4. Increasing Na+ and Ca2+ inflow into SA node cells

D. Increasing Na+ and Ca2+ inflow into SA nodes cells

184

What is ejection fraction?

  1. The percentage of the end-diastolic volume represented by the end-systolic volume
  2. The percentage of the end-diastolic volume represented by the stroke volume
  3. The percentage of the cardiac output represented by the stroke volume
  4. The percentage of normal stroke volume represented by the actual stroke volume

B. The percentage of end-diastolic volume represented by the stroke volume

185

Which of the following is an effect of norepinephrine on the heart?

  1. All of the listed statements are correct.
  2. The heart rate increases.
  3. The ventricles contract more forcefully.
  4. The ejection fraction increases.

A. All of the listed statements are correct.

186

The amount of blood pumped out of each ventricle during a single beat is the __________.

  1. stroke volume
  2. end-systolic volume
  3. cardiac output
  4. end-diastolic volume

A. stroke volume

187

What factors would make stroke volume greater?

  1. Increased end-diastolic volume and decreased end-systolic volume
  2. Decreased end-diastolic volume and decreased end-systolic volume
  3. Increased end-diastolic volume and increased end-systolic volume
  4. Decreased end-diastolic volume and decreased end-systolic volume

A. Increased end-diastolic volume and decreased end-systolic volume

188

Which factor does NOT increase stroke volume?

  1. Increased ventricular contractility
  2. Increased venous return
  3. Increased sympathetic stimulation
  4. Increased heart rate

D. Increased heart rate (would decrease stroke volume/less time to fill)

189

Which of the following is measured in milliliters per beat?

  1. Stroke volume
  2. Intermodal pathway
  3. End-systolic volume
  4. Heart rate

A. stroke volume

190

What is the term for the volume of blood that is left in the ventricle after the QRS wave?

  1. End-diastolic volume
  2. End-systolic volume
  3. Stroke volume
  4. Afterload

B. end-systolic volume

191

Under normal circumstances, the factors responsible for making delicate adjustments to the heart rate as circulatory demands change are __________.

  1. All of the listed responses are correct.
  2. autonomic activity and circulatory hormones
  3. somatic nerve activity and muscular activity
  4. cardiac output and stroke volume

B. autonomic activity and circulatory hormones

192

During exercise, the most important control mechanism to increase cardiac output is __________.

  1. increased body temperature
  2. increased acetylcholine release from the vagus nerve
  3. increased sympathetic activity to the ventricles
  4. increased end-systolic volume

C. increased sympathetic activity to the ventricles

193

What is meant by cardiac reserves?

  1. The difference between resting cardiac output and maximum cardiac output
  2. The blood held in reserve in systolic veins
  3. The potential increase in stroke volume during exercise
  4. The extra blood in the ventricle that is not ejected in the normal cardiac cycle

A. The difference between resting cardiac output and maximum cardiac output

194

What is meant by the term afterload?

  1. How much tension or force the ventricle has to generate to push the blood out of the ventricle
  2. How much blood is left in the ventricle after contraction
  3. The stretch of the ventricle muscle
  4. The pressure needed to close the semilunar valves

A. How much tension or force the ventricle has to generate to push the blood out of the ventricle

195

What effect does epinephrine have on the SA node?

  1. It increases the plateau.
  2. It increases heart rate.
  3. It increases hyperpolarization.
  4. It decreases heart rate.

B. It increases heart rate

196

Which of these organs is not found in the mediastinum?

  1. lungs
  2. esophagus
  3. trachea
  4. pericardial sac

A. lungs

197

Which wave is the largest in the electrocardiogram?

  1. P
  2. R
  3. S
  4. Q

B. R wave

198

Ventricular systole begins with the __________.

  1. opening of the aortic valve
  2. opening of the mitral valve
  3. closing of the aortic valve
  4. closing of the mitral valve

D. closing of the mitral valve

199

The wall of the left ventricle is thicker than the right; the left ventricle pumps more blood than the right. Are these two statements true or false?

  1. Both statements are true.
  2. The first is false; the second is true.
  3. The first is true; the second is false.
  4. Both statements are false.

C. The first is true, second is false

200

Which of these is not needed to determine cardiac output?

  1. blood pressure
  2. heart rate
  3. end diastolic volume
  4. end systolic volume

A. blood pressure

201

Which of these responses by the heart will sympathetic stimulation not cause?

  1. increased end-systolic volume
  2. increased stroke volume
  3. increased cardiac output
  4. increased heart rate

A. Increased end-systolic volume

202

The heart is actually (one, two, or three) pumps?

2 (pulmonary circuit and the systemic circuit)

203

Which heart chamber pumps unoxygenated blood out the pulmonary trunk?

  1. right ventricle
  2. left ventricle
  3. left atrium
  4. right atrium

A. the right ventricle (to the lungs)

204

Which heart chamber receives blood from the pulmonary veins?

  1. right ventricle
  2. left atrium
  3. left ventricle
  4. right atrium

B.left atrium

205

Which chamber pumps oxygenated blood out the aorta to the systemic circuit?

  1. right atrium
  2. right ventricle
  3. left ventricle
  4. left atrium

C. left ventricle

206

Isovolumetric relaxation and ventricular filling (two phases of the cardiac cycle) take place during __________.

  1. ventricular systole
  2. ventricular diastole

B. ventricular diastole

207

Which of the following is correct about the filling of the ventricles?

  1. Most blood flows passively into the ventricles through open AV valves.
  2. The majority of ventricular filling is caused by contraction of the atria.

A. blood flows passively into the ventricles through open AV valves.

208

Describe the pressures in the atria and ventricles that would cause the opening of the AV valves.

  1. Pressure in the atria would be greater than the pressure in the ventricles.
  2. Pressure in the ventricles would be greater than in the atria.
  3. Pressures in the atria and ventricles would be equal.

A. Pressure in the atria would be greater than the pressure in the ventricles (higher pressure in the atria than in the ventricles forces the AV valves to open and blood moves into the ventricles).

209

What causes the aortic semilunar valve to close?

  1. greater pressure in the aorta than in the left ventricle
  2. equal ventricular and aortic pressures
  3. higher ventricular pressure than aortic pressure

A. greater pressure in the aorta than in the left ventricle

210

Put the phases of the cardiac cycle in the correct order, starting after ventricular filling.

  1. isovolumetric relaxation, ventricular ejection, isovolumetric contraction
  2. isovolumetric contraction, ventricular ejection, isovolumetric relaxation
  3. ventricular ejection, isovolumetric contraction, isovolumetric relaxation
  4. ventricular ejection, ventricular relaxation, isovolumetric contraction

B.isovolumetric contraction, ventricular ejection, isovolumetric relaxation

211

Increased pressure in the ventricles would close what valve(s)?

  1. semilunar valves only
  2. AV valves only
  3. both semilunar and AV valves

B. AV valves only

212

Stewart suffers from bradycardia. Which type of drug might be a candidate to treat his condition?

  1. digitalis
  2. glucagon
  3. beta-adrenergic antagonists
  4. calcium channel blockers

B. glucagon (increases heart rate and myocardial contractility, and improves atrioventricular conduction)

213

How is heart rate controlled?

  1. Parasympathetic and sympathetic divisions of the ANS control heart rate.
  2. Dual innervation controls the heart rate.
  3. Heart rate is controlled through the cardiac plexus.
  4. All the listed answers are correct.

D. All the listed answers are correct.

214

With the force of the head-on collision, the patient’s chest collided with the steering wheel, causing fractures of the anterior chest wall, including the sternum and ribs. The heart itself, located just deep to the sternum, was injured and began bleeding into the pericardial cavity. What is normally found in the pericardial cavity?

  1. synovial fluid
  2. air
  3. pericardial fluid
  4. blood

C. pericardial fluid

215

Dr. Jim knew this victim was suffering from cardiac tamponade due to blood in the pericardial space. The blood in the pericardial cavity compressed the heart, squeezing the atria and ventricles so the atria could not fill. What vessels fill the right atria?

  1. pulmonary arteries
  2. superior and inferior vena cava
  3. aorta
  4. pulmonary veins

B. superior and inferior vena cava

216

Identify the most muscular chamber.

  1. Right ventricle
  2. Left atrium
  3. Left ventricle
  4. Right atrium

The left ventricle (the left ventricle is responsible for pumping blood out to the body)

217

Name the inner lining of the heart.

  1. Endocardium
  2. Myocardium
  3. Epicardium
  4. Pericardium

A. endocardium (The endocardium is the smooth, slick lining of the chambers of the heart. Endocardium is a continuation of endothelium that lines blood vessels. Both endocardium and endothelium are composed of simple squamous epithelial tissue, which minimizes friction between the wall of the chamber/vessel and the blood.)

218

Name the needle like ridges of muscle lining the ventricles.

  1. Trabeculae carneae
  2. Pectinate muscles
  3. Chordae tendineae
  4. Papillary muscles

A. trabeculae carneae

219

Blood on the right never mixes with blood on the left, once the heart is fully developed. T/F

True. Once fetal modifications (i.e. foramen ovale, ductus arteriosus) close following delivery of the infant, blood on the right side of the heart should not mix with blood on the left side of the heart.

220

What is the function of the coronary circulation?

  1. Provide a blood supply to the lungs
  2. Provide a blood supply to the aortic arch
  3. Provide a blood supply to the heart
  4. Provide a blood supply to the pericardium

C. Provide a blood supply to the heart (the coronary circulation provides oxygenated blood to the heart through coronary arteries)

221

What is the ligamentum arteriosum?

  1. A remnant of the foramen ovale
  2. A ligament securing the aorta
  3. A remnant of the ductus arteriosus
  4. A ligament attaching the aorta to the superior vena cava

C. a remnant of the ductus arteriosus (the ductus arteriosus is a fetal shunt that connects the pulmonary trunk to the aorta).

222

Which chamber of the heart exits into the pulmonary trunk?

  1. Right ventricle
  2. Left ventricle
  3. Left atrium
  4. Right atrium

A. The right ventricle pumps deoxygenated blood through the pulmonary semilunar valve into the pulmonary trunk to be distributed to the lungs.

223

The first branch off the arch of the aorta is the brachiocephalic artery in both the sheep and the human. T/F

True (the brachiocephalic artery is the first major vessel to exit the arch of the aorta)

224

What does the ECG wave tracing represent?

  1. electrical activity in the heart
  2. contraction of the heart

A. electrical activity in the heart

225

What does the QRS complex represent in the ECG wave tracing?

  1. ventricular depolarization
  2. atrial depolarization
  3. ventricular repolarization
  4. atrial repolarization

A. ventricular depolarization

226

Which part of the intrinsic conduction system delays the impulse briefly before it moves on to the ventricles?

  1. AV node
  2. SA node
  3. Bundles
  4. Perkinje fibers

A. AV node (slows down the impulse giving the atria time to contract before the ventricles contract)

227

Which of the following statements is true about the SA (sinoatrial) node?

  1. It is embedded in the posterior wall of the right atrium.
  2. The rate of spontaneous depolarization of SA nodal cells is the fastest in the SA node.
  3. The pacemaker cells, which establish the heart rate, are located in the SA node.
  4. All of these statements about the SA node are true.

D. All of these statements about the SA node are true.

228

Passive refilling of the heart occurs during which phase of the cardiac cycle?

  1. isovolumetric contraction
  2. ventricular diastole
  3. atrial diastole
  4. ventricular systole

B. ventricular diastole

229

Which of the following factors will decrease cardiac output?

  1. sympathetic activation
  2. increased venous return
  3. stimulation of the vagus nerve
  4. increased preload

C. stimulation of the vagus nerve (parasympathetic stimulation comes from the vagus nerve)

230

If you know both the heart rate and stroke volume, you can calculate the __________.

  1. end-systolic volume
  2. end-diastolic volume
  3. ejection fraction
  4. cardiac output

D. cardiac output

231

The __________ valve prevents backward flow of blood into the left ventricle.

  1. aortic
  2. bicuspid
  3. pulmonic
  4. tricuspid

A. aortic

232

Heart rate is controlled by __________.

  1. the right vagus nerve
  2. both the right vagus and sympathetic nerves
  3. sympathetic nerves in the cardiac plexus
  4. the phrenic nerves

B. both the right vagus and sympathetic nerves

233

The P wave of the electrocardiogram is closely followed by __________.

  1. relaxation of both atria
  2. contraction of the right atrium
  3. contraction of both atria
  4. contraction of the left atrium

C. contraction of both atria

234

Which of these is an important difference between cardiac muscle and skeletal muscle?

  1. Skeletal muscle is striated.
  2. Cardiac muscle can't be tetanized.
  3. Cardiac muscle lacks troponin.
  4. Cardiac muscle contracts spontaneously.

B. Cardiac muscle can't be tetanized

235

The rapid depolarization phase in the ventricular action potential appears in the electrocardiogram as the __________.

  1. T wave
  2. PR segment
  3. P wave
  4. QRS complex

D. QRS complex

236

The plateau phase of the ventricular action potential corresponds to the __________ phase of the electrocardiogram.

  1. PR interval
  2. ST segment
  3. T wave

B. ST segment

237

The duration of the ventricular action potential is approximately equal to the __________ interval in the electrocardiogram.

  1. PR interval
  2. ST interval
  3. QRS duration
  4. Q-T interval

D. Q-T interval

238

During ventricular systole the blood pressure __________ and ventricular volume __________.

  1. decreases; increases
  2. increases; increases
  3. decreases; decreases
  4. increases; decreases

D. increases; decreases

239

The volume of blood remaining in the ventricle as diastole begins is called the __________.

  1. end-systolic volume
  2. stroke volume
  3. cardiac reserve
  4. end-diastolic volume

A. end-systolic volume

240

Which of these statements concerning the cardiac cycle is false?

  1. Aortic pressure is greater than pulmonary trunk pressure.
  2. Cardiac cycle begins with atrial systole.
  3. AV valves close before semilunar valves open.
  4. Ventricular systole begins at the peak of atrial systole.

D. Ventricular systole begins at the peak of atrial systole.

241

Which of the following will not increase heart rate?

  1. increased sympathetic stimulation of the SA node
  2. faster rise of the pacemaker potential
  3. increased levels of circulating epinephrine
  4. increased parasympathetic stimulation of the SA node

D. increased parasympathetic stimulation of the SA node

242

Which of the following descriptions matches the term at the level of the third costal cartilage?

A) pericardial cavity

B) visceral pericardium

C) base of heart

D) aorta

E) right atrium

C) base of heart

243

In a(n) _______ part of the coronary circulation becomes blocked, and cardiac muscle cells die from lack of oxygen.

A) coronary spasm.

B) myocardial infarction.

C) coronary thrombosis.

D) angina pectoris.

E) pulmonary embolism.

B) myocardial infarction.

244

Blood is supplied to the muscular wall of the right atrium by the

A) brachiocephalic artery.

B) right coronary artery.

C) left coronary artery.

D) phrenic arteries.

E) pulmonary arteries.

B) right coronary artery (supplies right atrium, portions of both ventricles, portions of the conducting system)

245

Why is the left ventricle much larger than the right ventricle?

It has to pump blood through the large systemic circuit, the right ventricle only has to pump blood to the lungs.

246

The great cardiac vein drains blood from the heart muscle to the

(a) left ventricle,

(b) right ventricle,

(c) right atrium,

(d) left atrium.

(c) right atrium

247

The serous membrane covering the outer surface of the heart is the

(a) parietal pericardium,

(b) endocardium,

(c) myocardium,

(d) visceral pericardium.

(d) visceral pericardium.

248

The simple squamous epithelium covering the heart valves is the

(a) epicardium,

(b) endocardium,

(c) myocardium,

(d) cardiac skeleton.

(b) endocardium

249

The heart is surrounded by the

(a) pleural cavity,

(b) peritoneal cavity,

(c) abdominopelvic cavity,

(d) mediastinum,

(e) abdominal cavity.

(d) mediastinum

250

The cardiac skeleton of the heart has which two of the following functions?

(a) It physically isolates the muscle fibers of the atria from those of the ventricles,

(b) It maintains the normal shape of the heart,

(c) It helps distribute the forces of cardiac contraction,

(d) It allows more rapid contraction of the ventricles,

(e) It strengthens and helps prevent overexpansion of the heart.

(a) It physically isolates the muscle fibers of the atria from those of the ventricles

(b) It maintains the normal shape of the heart

251

Cardiac output is equal to the

(a) difference between the end-diastolic volume and the end-systolic volume,

(b) product of heart rate and stroke volume,

(c) difference between the stroke volume at rest and the stroke volume during exercise,

(d) stroke volume less the end-systolic volume,

(e) product of heart rate and blood pressure.

(b) product of heart rate and stroke volume

252

During diastole, a chamber of the heart

(a) relaxes and fills with blood,

(b) contracts and pushes blood into an adjacent chamber,

(c) experiences a sharp increase in pressure,

(d) reaches a pressure of approximately 120 mm Hg.

(a) relaxes and fills with blood

253

During the cardiac cycle, the amount of blood ejected from the left ventricle when the semilunar valve opens is the

(a) stroke volume (SV),

(b) end-diastolic volume (EDV),

(c) end-systolic volume (ESV),

(d) cardiac output (CO).

(a) stroke volume (SV)

254

The cells of the conducting system differ from the contractile cells of the heart in that

(a) conducting cells are larger and contain more myofibrils,

(b) contractile cells exhibit prepotentials,

(c) contractile cells do not normally exhibit automaticity,

(d) both a and b are correct.

(c) contractile cells do not normally exhibit automaticity

255

Which of the following is longer?

(a) the refractory period of cardiac muscle,

(b) the refractory period of skeletal muscle.

(a) the refractory period of cardiac muscle

256

If the papillary muscles fail to contract,

(a) the ventricles will not pump blood,

(b) the atria will not pump blood,

(c) the semilunar valves will not open,

(d) the AV valves will not close properly,

(e) none of these happen.

(d) the AV valves will not close properly

257

Cardiac output cannot increase indefinitely because

(a) the available filling time becomes shorter as the heart rate increases,

(b) the cardiovascular centers adjust the heart rate,

(c) the rate of spontaneous depolarization decreases,

(d) the ion concentrations of pacemaker plasma membranes decrease.

(a) the available filling time becomes shorter as the heart rate increases

258

What role do the chordae tendineae and papillary muscles play in the normal function of the AV valves?

Papillary muscles pull on the chordae tendineae which stops the cusps of the AV valves from swinging into the atria/stops backflow

259

What are the valves in the heart, and what is the function of each?

Right and left AV prevent regurgitation, semilunar valves prevent regurgitation from aorta and pulmonary trunk into left and right ventricles

260

Describe the three distinct layers that make up the heart wall.

(1) The epicardium is the visceral pericardium, which covers the outer surface of the heart. (2) The myocardium is the muscular wall of the heart, which forms both atria and ventricles. It contains cardiac muscle tissue and associated connective tissues, blood vessels, and nerves. (3) The endocardium is a squamous epithelium that covers the inner surfaces of the heart, including the valves.

261

Trace the normal pathway of an electrical impulse through the conducting system of the heart.

SA node, internodal pathways, AV node, AV bundle, bundle branches, Purkinje fibers

262

What is the cardiac cycle? What phases and events are necessary to complete a cardiac cycle?

The cardiac cycle comprises the events in a complete heartbeat. The cycle begins with atrial systole as the atria contract and push blood into the relaxed ventricles. As the atria relax (atrial diastole), the ventricles contract (ventricular systole), forcing blood through the semilunar valves into the pulmonary trunk and aorta. The ventricles then relax (ventricular diastole). For the rest of the cardiac cycle, both the atria and ventricles are in diastole; passive filling occurs.

263

What three factors regulate stroke volume to ensure that the left and right ventricles pump equal volumes of blood?

Preload - stretch on heart before it contracts

Contractility - forcefulness of contraction

Afterload - pressure that must be exceeded for blood to be ejected from ventricles

264

Describe the function of the SA node in the cardiac cycle. How does this function differ from that of the AV node?

SA node is pacemaker, AV node slows impulse

265

What are the sources and significance of the four heart sounds?

The first sound (lubb) marks the start of ventricular contraction, is produced as the AV valves close and the semilunar valves open. The second sound (dupp) occurs when the semilunar valves close and the AV valves open, marking the start of ventricular diastole. The third heart sound is associated with blood flow into the ventricles, and the fourth sound is associated with atrial contraction.

266

Differentiate between stroke volume and cardiac output. How is cardiac output calculated?

SV is volume of blood ejected by ventricle in single contraction (SV = EDV - ESV). CO is amount of blood pumped by left ventricle in one minute (CO = HR x SV)

267

What factors influence cardiac output?

Stroke volume and heart rate

268

What effect does sympathetic stimulation have on the heart? What effect does parasympathetic stimulation have on the heart?

Sympathetic excites, parasympathetic calms

269

Describe the effects of epinephrine, norepinephrine, glucagon, and thyroid hormones on the contractility of the heart.

Excite, increase cardiac contraction

270

What neurotransmitter does the vagus nerve release?

  1. cortisol
  2. epinephrine
  3. acetylcholine
  4. aldosterone

C. acetylcholine

271

The epicardium

A) is also known as the parietal pericardium.

B) is a layer of cardiac muscle.

C) is the visceral pericardium.

D) lines the heart chambers.

E) is the pacemaker of the heart.

C) is the visceral pericardium.

272

The heart valves have a double layer of __________ with a layer of __________ in between.

A) epicardium, myocardium

B) epicardium, endocardium

C) myocardium, endocardium

D) endocardium, connective tissue

E) connective tissue, epicardium

D) endocardium, connective tissue

273

Musculi pectinati are found in the __________ ; trabeculae carneae are found in the __________ .

A) auricles, auricles

B) auricles, ventricles

C) ventricles, auricles

D) ventricles, ventricles

B) auricles, ventricles

274

The skeleton of the heart

A) electrically insulates the atria from the ventricles.

B) is composed of bones and cartilage.

C) is the location of the pacemaker.

D) is composed of calcified cardiac muscle.

A) electrically insulates the atria from the ventricles.

275

Which of these structures is NOT present in cardiac muscle cells?

A) desmosomes

B) gap junctions

C) smooth sarcoplasmic reticulum

D) terminal cisternae

E) transverse (T) tubules

D) terminal cisternae

276

If the SA node becomes damaged and nonfunctional, which of these is the most likely to occur?

A) The heart will stop.

B) The ventricles will contract, but the atria will stop.

C) Another part of the heart, possibly the AV node, will become the pacemaker.

D) The heart will beat faster.

E) The atria will keep contracting, but the ventricles will stop.

C) Another part of the heart, possibly the AV node, will become the pacemaker.

277

Which of these statements concerning cardiac muscle is correct?

A) Cardiac muscle has more sarcoplasmic reticulum than skeletal muscle.

B) Cardiac muscle has a prolonged period of slow repolarization called the plateau phase.

C) Cardiac muscle has a shorter refractory period than skeletal muscle.

D) Depolarization of cardiac muscle occurs when K+ and Na+ diffuse into the cell.

E) all of these are correct

B) Cardiac muscle has a prolonged period of slow repolarization called the plateau phase.

278

Action potentials pass rapidly from one cardiac muscle cell to another because of

A) intercalated disks and numerous gap junctions.

B) large nerves with branches going to each cardiac muscle cell.

C) the large voltage of cardiac action potentials.

D) the plateau phase of the action potential.

E) open Ca2+ channels.

A) intercalated disks and numerous gap junctions.

279

The depolarization phase of the cardiac muscle action potential occurs when

A) voltage-gated Ca2+ ion channels open.

B) voltage-gated K+ ion channels open.

C) voltage-gated Na+ ion channels open.

D) both b and c

C) voltage-gated Na+ ion channels open.

280

Early repolarization of cardiac muscle cells occurs when

A) voltage-gated Ca2+ ion channels open.

B) voltage-gated K+ ion channels open.

C) voltage-gated Na+ ion channels close.

D) both b and c

B) voltage-gated K+ ion channels open.

281

Which of these conditions occur in the cardiac muscle cell during the plateau phase?

A) voltage-gated Ca2+ ion channels are open

B) voltage-gated K+ ion channels are open

C) voltage-gated Na+ ion channels are closed

D) all of these

D) all of these

282

Which of these conditions occurs in the cardiac muscle cell during the final repolarization phase?

A) voltage-gated Ca2+ ion channels are open

B) voltage-gated K+ ion channels are open

C) voltage-gated Na+ ion channels are open

D) all of these

B) voltage-gated K+ ion channels are open (voltage-gated Ca2+ and Na+ ion channels are closed)

283

Unlike other cardiac muscle cells, the movement of __________ into the pacemaker cells is primarily responsible for the depolarization phase of the action potential.

A) Ca2+ ions

B) K+ ions

C) Na+ ions

D) Cl- ions

A) Ca2+ ions

284

Which of these conditions results in a prepotential in pacemaker cells?

A) Na+ ions move into the cell through specialized Na+ ion channels.

B) Membrane permeability to K+ ions increases.

C) Voltage-gated Ca2+ ion channels close.

D) all of these are correct

A) Na+ ions move into the cell through specialized Na+ ion channels.

285

During the QT interval of the EKG, the

A) atria contract and begin to relax.

B) atria relax.

C) ventricles contract and begin to relax.

D) ventricles relax.

C) ventricles contract and begin to relax.

286

Which of these conditions is most likely to cause bradycardia?

A) ectopic action potentials in the atria

B) damage to the tricuspid valve

C) excessive sympathetic stimulation

D) excessive parasympathetic stimulation

E) too much coffee

D) excessive parasympathetic stimulation

287

During the period of ejection in the cardiac cycle, the atrioventricular valves are __________ and the semilunar valves are __________ .

A) closed, closed

B) closed, open

C) open, closed

D) open, open

B) closed, open

288

Blood flows neither into nor out of the ventricles during

A) the period of isovolumic contraction.

B) the period of isovolumic relaxation.

C) systole.

D) diastole.

E) both a and b

E) both a and b

289

At the end of __________, the ventricles are 70% filled.

A) active ventricular filling

B) passive ventricular filling

C) ventricular diastole

D) ventricular systoleE)atrial systole

B) passive ventricular filling

290

The average end-diastolic volume of the ventricles is about __________, whereas the end-systolic volume is about __________ .

A) 125 mL, 55 mL

B) 125 mL, 0 mL

C) 0 mL, 55 mL

D) 0 mL, 125 mL

E) 55 mL, 125 mL

A) 125 mL, 55 mL

291

During the period of ejection, the left ventricular pressure reaches a high point of approximately

A) 20 mm Hg.

B) 60 mm Hg.

C) 80 mm Hg.

D) 100 mm Hg.

E) 120 mm Hg.

E) 120 mm Hg.

292

Preload

A) is the extent to which the ventricular walls are stretched.

B) if increased, causes a decrease in cardiac output.

C) is the pressure in the aorta which contracting ventricles must overcome.

D) is part of the extrinsic regulation of the heart.

E) all of these

A) is the extent to which the ventricular walls are stretched.

293

Increased venous return to the heart causes increased

A) stroke volume.

B) preload.

C) cardiac output.

D) force of contraction.

E) all of these

E) all of these

294

Parasympathetic nerve fibers

A) are carried to the heart through the Accessory nerve (XI).

B) extend to terminal ganglia within the wall of the heart.

C) release the neurotransmitter norepinephrine.

D) if stimulated, result in an increased heart rate.

E) if stimulated, greatly increase stroke volume.

B) extend to terminal ganglia within the wall of the heart.

295

When normal arterial blood pressure decreases, baroreceptors cause a response that

A) decreases heart rate.

B) decreases stroke volume.

C) returns blood pressure to normal.

D) results in parasympathetic stimulation of the heart.

E) all of these

C) returns blood pressure to normal.

296

If blood pH decreases and blood carbon dioxide increases,

A) heart rate increases.

B) stroke volume decreases.

C) increased parasympathetic stimulation of the heart occurs.

D) the change is detected by chemoreceptors in the pulmonary arteries.

E) all of these

A) heart rate increases.

297

Increased sympathetic stimulation of the heart

A) increases the force of ventricular contraction.

B) opens a larger number of calcium slow channels.

C) increases the heart rate.

D) increases cardiac output.

E) all of these

E) all of these

298

Generally, an increase in extracellular Ca2+ ions causes __________ force of contraction, and __________ heart rate.

A) decreased, decreased

B) decreased, increased

C) increased, decreased

D) increased, increased

C) increased, decreased

299

Excess K+ ions in cardiac tissue cause heart rate and stroke volume to __________ and decreased extracellular K+ ions result in a __________ in heart rate.

A) decrease, decrease

B) decrease, increase

C) increase, decrease

D) increase, increase

E) be unchanged, increase

A) decrease, decrease

300

What types of tissue comprises the vavles of the heart?

A. Dense regular connective tissue

B. Dense irregular connective tissue

C. Areolar connective tissue

D. Hyaline cartilage

E. Cardiac muscle tissue

B. Dense irregular connective tissue

301

Stimulation of this nerve reduces heart rate.

A. Cardiac accelerator nerve

B. Hypoglossal nerve

C. Medulla oblongata nerve

D. Vagus nerve

E. Phrenic nerve

D. Vagus nerve

302

Which of the below factors would increase stroke volume?

A. Increased preload, increased afterload, increased contractility

B. Decreased preload, decreased afterload, decreased contractility

C. Increased preload, decreased afterload, increased contractility

D. Decreased preload, increased afterload, increased contractility

E. Increased preload, increased afterload, decreased contractility

C. Increased preload, decreased afterload, increased contractility

303

Which of the below reduces heart rate?

A. Increased noradrenaline hormone

B. Increased thyroid hormone

C. Increased potassium levels

D. Increased calcium levels

E. Increased sympathetic stimulation

C. Increased potassium levels

304

Cardiac muscle fibres electrically connect to neighbouring fibres by

A. Desmosomes

B. Intermediate discs

C. Gap junctions

D. Contractile fibres

E. Chordae tendinae

C. Gap junctions

305

This electrical event represents repolarization of the ventricle.

A. R wave

B. T wave

C. S wave

D. P wave

E. Q wave

B. T wave

306

Damage to the__________ is referred to as heart block

A. SA node

B. AV valves

C. AV bundles

D. AV node

D. AV node

307

Which of the following is not an age-related change affecting the heart?

A. Atherosclerosis

B. Decline in cardiac reserve

C. Fibrosis of cardiac muscle

D. Thinning of the valve flaps

D. Thinning of the valve flaps

308

Select the correct statement about cardiac output

A. A slow heart rate increases end diastolic volume, stroke volume, and force of contraction

B. Decreased venous return will result in increased end diastolic volume

C. If a semilunar valve were partially obstructed, the end systolic volume in the affected ventricle would be decreased

D. Stroke volume increasees if end diastolic volume decreases

A. A slow heart rate increases end diastolic volume, stroke volume, and force of contraction

309

What happens to blood flow when there is coarctation of the aorta?

It is decreased


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