The Heart (Anatomy and Physiology) Practice Questions

81 multiple-choice questions on The heart for paramedic and EMT students, from Chapter 8 (Anatomy and Physiology). Read each question, pick your answer, then tap Show answer to check it and read the explanation.

81 practice questions

1. The muscular middle layer of the heart wall is the:

   1. A. Endocardium
   2. B. Epicardium
   3. C. Myocardium
   4. D. Pericardium
   Show answer

   Answer: C. Myocardium

   The heart wall has three layers: endocardium (inner), myocardium (muscle), and epicardium (outer).

2. The sac surrounding the heart is the:

   1. A. Mediastinum
   2. B. Endocardium
   3. C. Myocardium
   4. D. Pericardium
   Show answer

   Answer: D. Pericardium

   Blood or fluid in this sac can cause cardiac tamponade.

3. What is the correct path of blood through the heart?

   1. A. Left atrium, left ventricle, lungs, right atrium, right ventricle, aorta
   2. B. Right atrium, left atrium, lungs, right ventricle, left ventricle, aorta
   3. C. Right atrium, right ventricle, lungs, left atrium, left ventricle, aorta
   4. D. Right ventricle, right atrium, lungs, left ventricle, left atrium, aorta
   Show answer

   Answer: C. Right atrium, right ventricle, lungs, left atrium, left ventricle, aorta

   Blood goes from the body into the right side, through the lungs, into the left side, and out to the body.

4. The valve between the left atrium and left ventricle is the:

   1. A. Pulmonic
   2. B. Aortic
   3. C. Tricuspid
   4. D. Mitral
   Show answer

   Answer: D. Mitral

   The mitral valve is also called the bicuspid valve. The mitral valve is on the left and the tricuspid on the right. Tip: the tricuspid comes before you "try" the lungs.

5. The chordae tendineae:

   1. A. Conduct impulses to the ventricles
   2. B. Supply blood to the valve leaflets
   3. C. Separate the right and left atria
   4. D. Tether AV valves to papillary muscles
   Show answer

   Answer: D. Tether AV valves to papillary muscles

   They anchor the atrioventricular valve leaflets to the papillary muscles. They keep the valves from flipping backward during contraction.

6. Blood leaving the right ventricle travels to the:

   1. A. Pulmonary veins and lungs
   2. B. Aorta and systemic circulation
   3. C. Left atrium via the septum
   4. D. Pulmonary artery and lungs
   Show answer

   Answer: D. Pulmonary artery and lungs

   The pulmonary artery is the only artery that carries deoxygenated blood.

7. The pulmonary veins carry:

   1. A. Deoxygenated blood to the lungs
   2. B. Deoxygenated blood to the right atrium
   3. C. Oxygenated blood to the aorta
   4. D. Oxygenated blood to the left atrium
   Show answer

   Answer: D. Oxygenated blood to the left atrium

   The pulmonary veins are the only veins that carry oxygenated blood.

8. The coronary arteries fill mainly during:

   1. A. Systole
   2. B. Isovolumetric contraction
   3. C. Diastole
   4. D. Atrial contraction
   Show answer

   Answer: C. Diastole

   Fast heart rates shorten diastole, which reduces coronary perfusion.

9. The left anterior descending (LAD) artery supplies the:

   1. A. Inferior wall and AV node
   2. B. Right atrium and SA node
   3. C. Right ventricle and posterior wall
   4. D. Anterior LV and septum
   Show answer

   Answer: D. Anterior LV and septum

   The LAD supplies the anterior left ventricle and the interventricular septum. An LAD occlusion causes a large anterior MI and is sometimes called the widowmaker.

10. What is the heart's primary pacemaker, and what is its intrinsic rate?

    1. A. SA node, 60-100 bpm
    2. B. Bundle of His, 60-100 bpm
    3. C. AV node, 40-60 bpm
    4. D. Purkinje fibers, 20-40 bpm
    Show answer

    Answer: A. SA node, 60-100 bpm

    Backup pacemakers are slower: the AV junction fires at 40-60 bpm and the ventricles at 20-40 bpm.

11. What is the correct order of the cardiac conduction system?

    1. A. AV node, SA node, bundle of His, bundle branches, Purkinje fibers
    2. B. SA node, AV node, bundle of His, bundle branches, Purkinje fibers
    3. C. SA node, bundle of His, AV node, bundle branches, Purkinje fibers
    4. D. SA node, AV node, bundle branches, bundle of His, Purkinje fibers
    Show answer

    Answer: B. SA node, AV node, bundle of His, bundle branches, Purkinje fibers

    The AV node's delay gives the atria time to fill the ventricles.

12. Cardiac output equals:

    1. A. Stroke volume / heart rate
    2. B. Preload x afterload
    3. C. Heart rate x stroke volume
    4. D. Blood pressure x heart rate
    Show answer

    Answer: C. Heart rate x stroke volume

    For example, 70 bpm x 70 mL is about 5 L/min.

13. Stroke volume is determined by:

    1. A. Blood viscosity and vessel length
    2. B. Cardiac output and SVR
    3. C. Preload, afterload, and contractility
    4. D. Heart rate alone, regardless of volume
    Show answer

    Answer: C. Preload, afterload, and contractility

    These three factors set how much blood is ejected with each beat. Cardiac output times systemic vascular resistance gives blood pressure, not stroke volume.

14. Preload is:

    1. A. Resistance the ventricle must pump against
    2. B. End-diastolic ventricular volume and stretch
    3. C. Volume of blood ejected with each beat
    4. D. Force generated by the atria during systole
    Show answer

    Answer: B. End-diastolic ventricular volume and stretch

    Preload is the volume of blood and stretch in the ventricle at the end of diastole. Blood loss lowers preload, which is why IV fluids can raise cardiac output.

15. Afterload is:

    1. A. Resistance the ventricle faces
    2. B. Volume of blood returning to the heart
    3. C. Blood flow through the coronary arteries
    4. D. Electrical activity of the ventricle
    Show answer

    Answer: A. Resistance the ventricle faces

    Hypertension raises afterload and makes the heart work harder.

16. The Frank-Starling mechanism states that:

    1. A. Contractility is fixed regardless of filling
    2. B. Greater stretch yields stronger contraction
    3. C. Higher afterload yields stronger contraction
    4. D. Heart rate rises as blood pressure falls
    Show answer

    Answer: B. Greater stretch yields stronger contraction

    Increased myocardial stretch, within limits, increases the force of contraction. More filling means more stretch and a stronger contraction, up to a point.

17. A normal ejection fraction is approximately:

    1. A. 55-70%
    2. B. 90-100%
    3. C. 20-30%
    4. D. 35-45%
    Show answer

    Answer: A. 55-70%

    Ejection fraction is the percentage of blood the left ventricle pumps out with each beat. It is low in heart failure.

18. The heart is located in the:

    1. A. Upper abdominal cavity
    2. B. Mediastinum
    3. C. Left pleural space
    4. D. Right pleural space
    Show answer

    Answer: B. Mediastinum

    The mediastinum lies behind the sternum, between the lungs. About two-thirds lies left of the midline.

19. The apex of the heart points:

    1. A. Upward and posteriorly
    2. B. Downward and to the left
    3. C. Upward and to the right
    4. D. Downward and to the right
    Show answer

    Answer: B. Downward and to the left

    The apical pulse is felt near the fifth intercostal space.

20. The endocardium is:

    1. A. The muscular layer of the heart wall
    2. B. The inner lining of the chambers
    3. C. The outer layer of the heart wall
    4. D. The fibrous sac around the heart
    Show answer

    Answer: B. The inner lining of the chambers

    It is continuous with the vessel lining.

21. The visceral pericardium is also called the:

    1. A. Parietal pericardium
    2. B. Endocardium
    3. C. Epicardium
    4. D. Myocardium
    Show answer

    Answer: C. Epicardium

    It adheres to the heart's surface.

22. Pericardial fluid functions to:

    1. A. Cushion the heart against blows
    2. B. Insulate the conduction system
    3. C. Nourish the outer myocardial layer
    4. D. Reduce friction during beats
    Show answer

    Answer: D. Reduce friction during beats

    Normally only a small amount is present.

23. Cardiac tamponade impairs the heart primarily by:

    1. A. Directly weakening contractility
    2. B. Triggering ventricular dysrhythmias
    3. C. Preventing ventricular filling
    4. D. Compressing the coronary arteries
    Show answer

    Answer: C. Preventing ventricular filling

    Even small volumes can be critical if accumulation is rapid.

24. The right atrium receives blood from the:

    1. A. Left ventricle via the septum
    2. B. Aorta and pulmonary artery
    3. C. Pulmonary veins and coronary arteries
    4. D. Venae cavae and coronary sinus
    Show answer

    Answer: D. Venae cavae and coronary sinus

    It receives the superior and inferior venae cavae and the coronary sinus. This blood is oxygen-poor.

25. The tricuspid valve lies between the:

    1. A. Left atrium and left ventricle
    2. B. Left ventricle and aorta
    3. C. Right ventricle and pulmonary artery
    4. D. Right atrium and right ventricle
    Show answer

    Answer: D. Right atrium and right ventricle

    It has three cusps.

26. The pulmonic valve lies between the:

    1. A. Left ventricle and the ascending aorta
    2. B. Right ventricle and pulmonary artery
    3. C. Left atrium and left ventricle
    4. D. Right atrium and right ventricle
    Show answer

    Answer: B. Right ventricle and pulmonary artery

    It is a semilunar valve.

27. The aortic valve prevents:

    1. A. Backflow into the coronary arteries
    2. B. Backflow from ventricle into atrium
    3. C. Backflow into the left ventricle
    4. D. Backflow from the pulmonary veins
    Show answer

    Answer: C. Backflow into the left ventricle

    It stops blood in the aorta from flowing back into the left ventricle during diastole. The coronary arteries originate just beyond it.

28. The left ventricle wall is thicker than the right because it:

    1. A. Faces higher systemic resistance
    2. B. Contracts at a faster rate
    3. C. Holds a larger volume of blood
    4. D. Contains more valves and chordae
    Show answer

    Answer: A. Faces higher systemic resistance

    The left ventricle pumps against high systemic vascular resistance, so its muscle wall is thicker; the right ventricle faces low pulmonary resistance. Both ventricles beat at the same rate and eject about the same stroke volume, and each has an inflow valve with chordae and an outflow valve, so none of these explains the difference.

29. Papillary muscles function to:

    1. A. Anchor the chordae tendineae
    2. B. Conduct impulses to the septum
    3. C. Produce pericardial fluid
    4. D. Contract the atria before systole
    Show answer

    Answer: A. Anchor the chordae tendineae

    Through the chordae, they prevent AV valve prolapse. They contract with the ventricles.

30. The interventricular septum:

    1. A. Separates the two atria
    2. B. Separates the heart from the lungs
    3. C. Forms the inner pericardial layer
    4. D. Separates the two ventricles
    Show answer

    Answer: D. Separates the two ventricles

    It also carries the bundle of His and bundle branches. Septal infarction disrupts conduction.

31. Systole refers to:

    1. A. Ventricular relaxation and filling
    2. B. Ventricular contraction and ejection
    3. C. The period of coronary perfusion
    4. D. Atrial filling from the venae cavae
    Show answer

    Answer: B. Ventricular contraction and ejection

    Diastole is the relaxation and filling phase.

32. Most ventricular filling occurs:

    1. A. During isovolumetric contraction
    2. B. During ventricular systole
    3. C. During atrial contraction alone
    4. D. Passively, early in diastole
    Show answer

    Answer: D. Passively, early in diastole

    Atrial contraction then adds a final portion. The atrial kick contributes roughly 20 to 30 percent.

33. Loss of the atrial kick in atrial fibrillation:

    1. A. Increases stroke volume
    2. B. Improves ventricular filling
    3. C. Reduces cardiac output
    4. D. Has no effect on cardiac output
    Show answer

    Answer: C. Reduces cardiac output

    The drop matters most in patients with limited cardiac reserve. It also raises the risk of clot formation.

34. Normal adult stroke volume is approximately:

    1. A. 300 mL
    2. B. 20 mL
    3. C. 150 mL
    4. D. 70 mL
    Show answer

    Answer: D. 70 mL

    It varies with preload, afterload, and contractility.

35. Ejection fraction is calculated as:

    1. A. Stroke volume times heart rate
    2. B. End-systolic volume / stroke volume
    3. C. Stroke volume / end-diastolic volume
    4. D. Cardiac output divided by heart rate
    Show answer

    Answer: C. Stroke volume / end-diastolic volume

    Normal is about 55 to 70 percent.

36. Cardiac output in an average adult at rest is approximately:

    1. A. 10 L/min
    2. B. 1 to 2 L/min
    3. C. 5 L/min
    4. D. 500 mL/min
    Show answer

    Answer: C. 5 L/min

    It rises substantially with exercise.

37. Which factor increases preload?

    1. A. Increased venous return
    2. B. Dehydration from vomiting
    3. C. Hemorrhage with volume loss
    4. D. Venous dilation from nitrates
    Show answer

    Answer: A. Increased venous return

    Fluid administration or leg elevation increases venous return. More filling generally means more stroke volume.

38. Which factor increases afterload?

    1. A. Hypovolemia from hemorrhage
    2. B. Peripheral vasodilation
    3. C. Systemic hypertension
    4. D. Bradycardia from vagal tone
    Show answer

    Answer: C. Systemic hypertension

    Vasoconstriction also raises afterload. Higher afterload reduces stroke volume.

39. Contractility refers to:

    1. A. Total circulating blood volume
    2. B. Intrinsic force of contraction
    3. C. End-diastolic ventricular stretch
    4. D. The rate of ventricular firing
    Show answer

    Answer: B. Intrinsic force of contraction

    It is the force of contraction independent of preload and afterload. Epinephrine increases it.

40. A positive inotropic drug:

    1. A. Lowers systemic vascular resistance
    2. B. Speeds conduction through the AV node
    3. C. Increases contraction force
    4. D. Slows the sinus node rate
    Show answer

    Answer: C. Increases contraction force

    Chronotropic affects rate; dromotropic affects conduction.

41. A negative chronotropic effect means:

    1. A. Decreased heart rate
    2. B. Increased contractility
    3. C. Slowed AV node conduction
    4. D. Increased heart rate and output
    Show answer

    Answer: A. Decreased heart rate

    Beta blockers produce it.

42. Automaticity refers to the ability of cardiac cells to:

    1. A. Store calcium for contraction
    2. B. Conduct impulses to neighboring cells
    3. C. Generate impulses spontaneously
    4. D. Contract when stimulated by nerves
    Show answer

    Answer: C. Generate impulses spontaneously

    It exists throughout the conduction system.

43. Conductivity refers to:

    1. A. Shortening in response to stimulus
    2. B. Transmitting impulses cell to cell
    3. C. Relaxing between contractions
    4. D. Generating impulses spontaneously
    Show answer

    Answer: B. Transmitting impulses cell to cell

    Intercalated discs facilitate it.

44. The AV node delays the impulse in order to:

    1. A. Protect the SA node from overdrive
    2. B. Block impulses from the ventricles
    3. C. Allow complete ventricular filling
    4. D. Slow the overall heart rate
    Show answer

    Answer: C. Allow complete ventricular filling

    The pause lets the atria finish emptying into the ventricles. The delay is roughly a tenth of a second.

45. The intrinsic rate of the AV junction is:

    1. A. 60 to 100 beats/min
    2. B. 20 to 40 beats/min
    3. C. 100 to 120 beats/min
    4. D. 40 to 60 beats/min
    Show answer

    Answer: D. 40 to 60 beats/min

    It takes over if the SA node fails.

46. The intrinsic rate of the ventricles is:

    1. A. 20 to 40 beats/min
    2. B. 40 to 60 beats/min
    3. C. 60 to 100 beats/min
    4. D. Over 100 beats/min
    Show answer

    Answer: A. 20 to 40 beats/min

    This escape rhythm is slow and unreliable.

47. The Purkinje fibers function to:

    1. A. Slow conduction to the ventricles
    2. B. Spread the impulse through ventricles
    3. C. Generate the primary cardiac impulse
    4. D. Delay the impulse at the AV junction
    Show answer

    Answer: B. Spread the impulse through ventricles

    They allow coordinated ventricular contraction.

48. Depolarization of a cardiac cell involves:

    1. A. Chloride entering the cell
    2. B. Sodium and calcium entering
    3. C. Potassium rushing into the cell
    4. D. Calcium leaving the cell
    Show answer

    Answer: B. Sodium and calcium entering

    The influx makes the cell interior positive. Contraction follows depolarization.

49. The plateau phase of the cardiac action potential is produced by:

    1. A. Calcium influx
    2. B. Sodium influx
    3. C. Chloride efflux
    4. D. Potassium influx
    Show answer

    Answer: A. Calcium influx

    Calcium influx prolongs contraction. It prevents tetany in cardiac muscle.

50. The absolute refractory period protects the heart by:

    1. A. Allowing rapid repeated restimulation
    2. B. Slowing conduction through the AV node
    3. C. Blocking response to a new impulse
    4. D. Increasing the heart rate
    Show answer

    Answer: C. Blocking response to a new impulse

    The cell cannot respond until it has recovered. A stimulus during the relative refractory period can trigger dysrhythmias.

51. The P wave on an ECG represents:

    1. A. Atrial repolarization
    2. B. Ventricular repolarization
    3. C. Atrial depolarization
    4. D. Ventricular depolarization
    Show answer

    Answer: C. Atrial depolarization

    It should precede each QRS in sinus rhythm.

52. The QRS complex represents:

    1. A. Atrial repolarization
    2. B. Ventricular repolarization
    3. C. Ventricular depolarization
    4. D. Atrial depolarization
    Show answer

    Answer: C. Ventricular depolarization

    A wide QRS suggests a ventricular origin or conduction delay.

53. The T wave represents:

    1. A. Atrial repolarization
    2. B. Ventricular repolarization
    3. C. Atrial depolarization
    4. D. Ventricular depolarization
    Show answer

    Answer: B. Ventricular repolarization

    Peaked T waves suggest hyperkalemia.

54. The coronary arteries originate from the:

    1. A. Left ventricle below the valve
    2. B. Pulmonary trunk above its valve
    3. C. Aorta just above the aortic valve
    4. D. Coronary sinus of the right atrium
    Show answer

    Answer: C. Aorta just above the aortic valve

    The left and right coronary arteries branch from there.

55. The right coronary artery typically supplies the:

    1. A. Right ventricle and inferior wall
    2. B. Left atrium and posterior septum
    3. C. Anterior wall and septum of the LV
    4. D. Lateral wall of the left ventricle
    Show answer

    Answer: A. Right ventricle and inferior wall

    In most people it also supplies the SA and AV nodes. Inferior MI often causes bradycardia for this reason.

56. The circumflex artery supplies the:

    1. A. Lateral wall of the left ventricle
    2. B. Inferior wall in most people
    3. C. Anterior septum and apex
    4. D. Free wall of the right ventricle
    Show answer

    Answer: A. Lateral wall of the left ventricle

    It also supplies part of the left atrium. It branches from the left main coronary artery.

57. An older patient in SVT at 170/min develops chest pain. The main reason is:

    1. A. Longer diastole overfills the coronary arteries
    2. B. Lengthened systole stretches and narrows the coronaries
    3. C. Shortened diastole cuts coronary filling as demand rises
    4. D. The SA node stops perfusing the myocardium at high rates
    Show answer

    Answer: C. Shortened diastole cuts coronary filling as demand rises

    Coronary arteries fill mainly during diastole. At fast rates, diastole shortens much more than systole, so coronary flow falls just as myocardial oxygen demand rises, which causes ischemia. Fast rates shorten diastole rather than lengthen it, and the SA node is a pacemaker, not a source of perfusion.

58. Myocardial oxygen demand increases with:

    1. A. Rest and reduced activity
    2. B. Bradycardia and low blood pressure
    3. C. Faster rate and higher afterload
    4. D. Peripheral vasodilation
    Show answer

    Answer: C. Faster rate and higher afterload

    Increased contractility also raises demand. This is the basis of angina during exertion.

59. Angina occurs when:

    1. A. A heart valve suddenly fails
    2. B. Myocardium has already infarcted
    3. C. Demand briefly exceeds supply
    4. D. The pericardial sac fills
    Show answer

    Answer: C. Demand briefly exceeds supply

    Rest and nitroglycerin typically relieve it.

60. Myocardial infarction differs from angina because:

    1. A. Coronary blood flow is unaffected
    2. B. It resolves with rest and nitro
    3. C. Myocardial cells die
    4. D. Its pain is sharp and positional
    Show answer

    Answer: C. Myocardial cells die

    Cell death results from prolonged ischemia. Time to reperfusion determines muscle salvaged. Both conditions involve reduced coronary flow. Sharp, positional pain suggests pericarditis rather than either one.

61. Heart failure occurs when:

    1. A. Output can't meet body needs
    2. B. The valves close too early
    3. C. Blood pressure rises too high
    4. D. Heart rate becomes too fast
    Show answer

    Answer: A. Output can't meet body needs

    It may affect one or both sides.

62. Right-sided heart failure produces:

    1. A. Wheezing and dyspnea
    2. B. Pink frothy sputum and hypoxia
    3. C. Crackles and orthopnea
    4. D. JVD and peripheral edema
    Show answer

    Answer: D. JVD and peripheral edema

    Liver enlargement may also occur. Blood backs up into the systemic venous system.

63. Left-sided heart failure produces:

    1. A. Dependent peripheral edema
    2. B. Jugular venous distention
    3. C. Pulmonary congestion
    4. D. Ascites and liver enlargement
    Show answer

    Answer: C. Pulmonary congestion

    Expect dyspnea, crackles, and orthopnea. Fluid backs up into the lungs.

64. Cardiac reserve refers to:

    1. A. Stroke volume at rest
    2. B. Resting cardiac output at baseline
    3. C. Ability to raise output on demand
    4. D. Blood held in the venous system
    Show answer

    Answer: C. Ability to raise output on demand

    It declines with age and with heart disease.

65. A dehydrated patient's blood pressure improves after a 500 mL fluid bolus. Which mechanism best explains the rise in stroke volume?

    1. A. Higher afterload increases the amount the heart ejects
    2. B. More preload stretches the ventricle, so it contracts harder
    3. C. Reduced venous return lowers the work the heart must do
    4. D. Reduced contractility lengthens filling time and output
    Show answer

    Answer: B. More preload stretches the ventricle, so it contracts harder

    The Frank-Starling mechanism means more ventricular filling (preload) stretches the fibers and produces a more forceful contraction, so more blood is ejected. Higher afterload reduces stroke volume. Fluid increases venous return rather than reducing it, and lower contractility would reduce output.

66. Valve stenosis refers to:

    1. A. A narrowed valve blocking flow
    2. B. A dilated chamber behind the valve
    3. C. A leaking valve that lets blood backflow
    4. D. A congenitally absent valve
    Show answer

    Answer: A. A narrowed valve blocking flow

    Regurgitation refers to backward leakage.

67. Endocarditis is:

    1. A. Inflammation of the myocardium itself
    2. B. Infection of the heart's inner lining
    3. C. Calcific narrowing of a valve
    4. D. Inflammation of the pericardial sac
    Show answer

    Answer: B. Infection of the heart's inner lining

    It commonly involves the valves. IV drug use is a risk factor.

68. Pericarditis typically produces pain that:

    1. A. Eases when leaning forward
    2. B. Worsens when sitting up
    3. C. Radiates to the back like tearing
    4. D. Is relieved by nitroglycerin
    Show answer

    Answer: A. Eases when leaning forward

    Pain typically worsens when lying flat. A friction rub may be heard. Tearing pain radiating to the back suggests aortic dissection.

69. Cardiomyopathy refers to:

    1. A. Narrowing of coronary arteries
    2. B. Disease of the cardiac valves
    3. C. Disease of the pericardium
    4. D. Disease of the heart muscle
    Show answer

    Answer: D. Disease of the heart muscle

    It may be dilated, hypertrophic, or restrictive.

70. Which structure carries the impulse from the AV node into the ventricles?

    1. A. Bundle of His and branches
    2. B. Internodal atrial pathways
    3. C. The coronary sinus
    4. D. Purkinje fibers alone
    Show answer

    Answer: A. Bundle of His and branches

    A blocked branch produces a bundle branch block.

71. Blood returning from the heart muscle itself drains into the:

    1. A. Aortic root
    2. B. Coronary sinus
    3. C. Pulmonary veins
    4. D. Left atrium
    Show answer

    Answer: B. Coronary sinus

    The coronary sinus empties into the right atrium. This is the venous side of coronary circulation.

72. Heart sounds S1 and S2 are produced by:

    1. A. Turbulent flow in the great arteries
    2. B. Opening of the semilunar valves
    3. C. Closure of AV, then semilunar valves
    4. D. Ventricular muscle contracting
    Show answer

    Answer: C. Closure of AV, then semilunar valves

    S1 is lub; S2 is dub.

73. Muffled heart sounds, jugular distention, and hypotension together suggest:

    1. A. Heart failure
    2. B. Cardiac tamponade
    3. C. Tension pneumothorax
    4. D. Pulmonary embolism
    Show answer

    Answer: B. Cardiac tamponade

    This combination is called Beck triad.

74. A normal heart rate is maintained by:

    1. A. The AV node acting as pacemaker
    2. B. SA node alone, without outside input
    3. C. Circulating hormones only
    4. D. SA node modified by autonomic input
    Show answer

    Answer: D. SA node modified by autonomic input

    Vagal tone slows the resting rate.

75. Vagal stimulation, such as bearing down, typically:

    1. A. Increases the heart rate
    2. B. Raises blood pressure
    3. C. Slows the heart rate
    4. D. Increases contractility
    Show answer

    Answer: C. Slows the heart rate

    It increases parasympathetic tone. Vagal maneuvers can terminate some tachycardias.

76. Which is the correct sequence of blood flow through the left heart?

    1. A. Pulmonary veins, left atrium, aortic valve, left ventricle, mitral valve, aorta
    2. B. Pulmonary veins, left atrium, mitral valve, left ventricle, aortic valve, aorta
    3. C. Pulmonary artery, left atrium, mitral valve, left ventricle, aortic valve, aorta
    4. D. Pulmonary veins, left ventricle, mitral valve, left atrium, aortic valve, aorta
    Show answer

    Answer: B. Pulmonary veins, left atrium, mitral valve, left ventricle, aortic valve, aorta

    Valves keep flow moving forward.

77. Chest compressions circulate blood by:

    1. A. Compressing the heart and chest
    2. B. Stimulating the SA node to fire
    3. C. Depolarizing the myocardium
    4. D. Increasing preload only
    Show answer

    Answer: A. Compressing the heart and chest

    Raised thoracic pressure moves blood forward. Interruptions quickly drop perfusion pressure.

78. Defibrillation works by:

    1. A. Restarting a stopped heart
    2. B. Depolarizing the myocardium at once
    3. C. Delivering oxygen to the heart
    4. D. Increasing myocardial contractility
    Show answer

    Answer: B. Depolarizing the myocardium at once

    Simultaneous depolarization lets an organized rhythm resume. It is useless in asystole.

79. The most common cause of coronary artery narrowing is:

    1. A. Coronary artery vasospasm
    2. B. Coronary artery embolism
    3. C. Spontaneous coronary dissection
    4. D. Atherosclerotic plaque
    Show answer

    Answer: D. Atherosclerotic plaque

    Plaque rupture triggers acute events. Coronary embolism and spontaneous coronary artery dissection are real but uncommon causes of coronary blockage.

80. Which change occurs in the aging heart?

    1. A. Higher maximum heart rate with age
    2. B. Faster conduction velocity
    3. C. More compliant ventricular walls
    4. D. Stiffer ventricles, less reserve
    Show answer

    Answer: D. Stiffer ventricles, less reserve

    Maximum heart rate also declines. Older patients compensate poorly for stress.

81. Myocardial cells differ from skeletal muscle cells in that they:

    1. A. Lack visible striations
    2. B. Contract as a coordinated unit
    3. C. Rely mainly on anaerobic metabolism
    4. D. Fatigue rapidly with exercise
    Show answer

    Answer: B. Contract as a coordinated unit

    Electrical coupling through intercalated discs links the cells. The heart functions as a functional syncytium. Cardiac muscle is striated like skeletal muscle, and it depends heavily on aerobic metabolism, with abundant mitochondria.