front 1 During strenuous exercise, cardiac output must usually: A. Fall below resting levels | back 1 C. Increase markedly |
front 2 During rhythmic exercise, muscle blood flow typically: A. Remains constant each beat | back 2 D. Oscillates with contraction |
front 3 During the contraction phase of normal exercise, muscle blood flow falls mainly because: A. Venous PO2 rises | back 3 C. Contracted fibers compress vessels |
front 4 During a strong tetanic contraction, muscle blood flow can be almost abolished because of: A. Sustained vascular compression | back 4 A. Sustained vascular compression |
front 5 A sustained tetanic contraction rapidly weakens primarily because: A. Lactic acid disappears | back 5 B. Blood flow is nearly stopped |
front 6 At rest, many skeletal muscle capillaries: A. Have maximal flow | back 6 C. Carry little or no flow |
front 7 During exercise, effective muscle capillary surface area usually increases by about: A. 25% | back 7 C. Two- to threefold |
front 8 A fall in interstitial oxygen concentration in active muscle has what direct vascular effect? A. Local arteriolar vasodilation | back 8 A. Local arteriolar vasodilation |
front 9 Which local change most strongly enhances muscle blood flow during exercise? A. Increased tissue oxygen | back 9 B. Decreased tissue oxygen |
front 10 Which set best sustains exercise hyperemia in active muscle? A. K+, ATP, lactate, CO2 | back 10 A. K+, ATP, lactate, CO2 |
front 11 Sympathetic vasoconstrictor nerve endings in muscle chiefly release: A. Epinephrine | back 11 D. Norepinephrine |
front 12 Maximal sympathetic stimulation of skeletal muscle vessels can reduce blood flow to about: A. One half to one third | back 12 A. One half to one third |
front 13 Circulating epinephrine causes slight skeletal muscle vasodilation mainly by stimulating: A. Alpha receptors | back 13 B. Beta receptors |
front 14 Alpha vasoconstrictor receptors are excited especially by: A. Norepinephrine | back 14 A. Norepinephrine |
front 15 Under resting conditions, the heart is normally restrained mainly by: A. Sympathetic inhibition | back 15 C. Parasympathetic inhibition |
front 16 At exercise onset, the rise in heart rate and contractility occurs first because of: A. Increased vagal discharge | back 16 B. Removal of vagal inhibition |
front 17 During heavy exercise, most peripheral arterioles are: A. Dilated, including inactive beds | back 17 B. Constricted, except active muscle |
front 18 Despite high sympathetic tone, active skeletal muscle still receives increased flow because: A. Venous pressure exceeds arterial | back 18 B. Local metabolites override constriction |
front 19 As blood flow to active muscle rises, flow to many nonmuscular tissues: A. Also rises equally | back 19 B. Falls because of redistribution |
front 20 During exercise, which two vascular beds are relatively spared from the generalized vasoconstriction affecting nonactive tissues? A. Renal and splanchnic | back 20 B. Coronary and cerebral |
front 21 Coronary and cerebral vessels are relatively spared during exercise mainly because they: A. Have high alpha tone | back 21 C. Need preserved perfusion |
front 22 Compared with many inactive vascular beds, coronary and cerebral circulations have relatively: A. Poor vasoconstrictor innervation | back 22 A. Poor vasoconstrictor innervation |
front 23 During exercise, sympathetic stimulation causes venous walls to: A. Relax diffusely | back 23 B. Contract powerfully |
front 24 Venoconstriction during exercise most directly increases: A. Pulmonary vascular resistance | back 24 B. Mean systemic filling pressure |
front 25 The major hemodynamic importance of exercise-induced venoconstriction is to increase: A. Capillary hydrostatic pressure | back 25 B. Venous return and cardiac output |
front 26 In active skeletal muscle during exercise, arterioles are predominantly: A. Vasoconstricted | back 26 C. Vasodilated |
front 27 In most nonactive tissues during exercise, the dominant arteriolar effect is: A. Vasodilation | back 27 B. Vasoconstriction |
front 28 The relatively modest pressure rise during massive whole-body exercise is best explained by: A. Global vagal dominance | back 28 B. Widespread muscle vasodilation |
front 29 Compared with an untrained runner, a trained marathon runner can increase cardiac output during maximal exercise: A. Less | back 29 C. More |
front 30 Raising the entire venous return curve during exercise requires: A. Lower MSFP, higher resistance | back 30 B. Higher MSFP, lower resistance |
front 31 In a person with a very strong heart during heavy exercise, right atrial pressure often: A. Rises above normal | back 31 B. Falls below normal Exercise → ↑ sympathetic stimulation → ↑ heart contractility + ↑ heart rate → right heart empties faster → ↓ blood left in right atrium → ↓ RAP |
front 32 The left coronary artery mainly supplies the: A. Right ventricle and septum | back 32 B. Anterior and left lateral LV |
front 33 The right coronary artery supplies most of the right ventricle and the: A. Anterior left ventricle | back 33 C. Posterior left ventricle |
front 34 Most venous blood from the left ventricular myocardium returns to the right atrium through the: A. Great cardiac vein | back 34 C. Coronary sinus |
front 35 Approximately what fraction of total coronary flow returns via the coronary sinus? A. About 25% | back 35 C. About 75% |
front 36 Most venous blood from the right ventricular myocardium returns directly to the right atrium through: A. Coronary sinus tributaries | back 36 B. Small anterior cardiac veins |
front 37 A tiny amount of coronary venous blood enters all chambers directly through: A. Vasa vasorum | back 37 D. Thebesian veins |
front 38 During strenuous exercise, myocardial work rises more than cardiac output because the heart also pumps against: A. Lower venous pressure | back 38 B. Higher arterial pressure |
front 39 A lifter performing intense arm exercise develops a marked rise in mean arterial pressure. Which pattern best explains this? A. Local vasoconstriction, systemic dilation | back 39 B. Local dilation, systemic constriction |
front 40 In the left ventricular myocardium, coronary capillary blood flow during systole normally: A. Decreases | back 40 A. Decreases |
front 41 The fall in left ventricular coronary capillary flow during systole occurs mainly because: A. Aortic pressure collapses | back 41 C. Myocardial contraction compresses vessels |
front 42 In the left ventricle, coronary capillary blood flow is greatest during: A. Isovolumic contraction | back 42 D. Diastole |
front 43 Compared with most other vascular beds, left ventricular coronary flow is unusual because it: A. Falls during systole | back 43 A. Falls during systole |
front 44 The coronary arteries on the outer surface of the heart are the: A. Septal arteries | back 44 C. Epicardial arteries |
front 45 Immediately beneath the endocardium lies a plexus of: A. Subendocardial arteries | back 45 A. Subendocardial arteries |
front 46 Whenever cardiac contractile vigor increases, coronary blood flow generally: A. Falls slightly | back 46 B. Also increases |
front 47 Coronary blood flow rises almost in what relationship to myocardial oxygen consumption? A. Inverse | back 47 C. Direct |
front 48 Very low intracellular oxygen causes breakdown of ATP first to: A. Creatine | back 48 B. ADP |
front 49 After ATP falls to ADP and then AMP, the next major breakdown product is: A. Adenosine | back 49 A. Adenosine |
front 50 Very low myocardial oxygen levels promote local coronary vasodilation mainly through release of: A. Potassium | back 50 D. Adenosine |
front 51 The oxygen level that most strongly triggers adenosine release is: A. Very low | back 51 A. Very low |
front 52 Coronary vasodilation from adenosine is most directly a response to: A. Increased venous pressure | back 52 B. Myocardial hypoxia |
front 53 Sympathetic stimulation of the heart generally: A. Decreases metabolism | back 53 C. Increases metabolism |
front 54 During sympathetic activation, coronary vessels dilate mainly because increased cardiac metabolism triggers: A. Local flow regulation | back 54 A. Local flow regulation So even though sympathetic nerves can cause some direct vasoconstriction, the main effect in coronary vessels is metabolic vasodilation → more coronary blood flow. |
front 55 During sympathetic stimulation, coronary blood flow rises roughly in proportion to cardiac: A. Heart rate only | back 55 D. Metabolic needs |
front 56 Vagal stimulation indirectly tends to constrict coronary arteries because it: A. Raises oxygen demand | back 56 C. Lowers cardiac oxygen use |
front 57 Despite that indirect effect, acetylcholine has what direct action on coronary arteries? A. Dilates them | back 57 A. Dilates them |
front 58 In coronary vessels, constrictor receptors are predominantly: A. Muscarinic | back 58 D. Alpha |
front 59 In coronary vessels, dilator receptors are predominantly: A. Alpha | back 59 B. Beta |
front 60 Epicardial coronary vessels have a relative predominance of: A. Alpha receptors | back 60 A. Alpha receptors |
front 61 Intramuscular coronary arteries may have a predominance of: A. Alpha receptors | back 61 C. Beta receptors |
front 62 The major controller of myocardial blood flow is: A. Sympathetic tone | back 62 B. Myocardial oxygen consumption |
front 63 Under resting conditions, the heart obtains most of its energy from: A. Glucose | back 63 D. Fatty acids |
front 64 Under ischemic or anaerobic conditions, cardiac muscle must rely more on: A. Fat oxidation | back 64 B. Anaerobic glycolysis |
front 65 During severe ischemia, chest pain is promoted partly by buildup of: A. Uric acid | back 65 C. Lactic acid |
front 66 During coronary hypoxia, which metabolite is believed to dilate coronary arterioles? A. Adenosine | back 66 A. Adenosine |
front 67 Why is prolonged coronary occlusion especially dangerous after 30 minutes? A. Coronary veins thrombose completely | back 67 B. Adenine resynthesis is very slow |
front 68 In atherosclerosis, the first major material deposited beneath the arterial endothelium is: A. Calcium | back 68 B. Cholesterol |
front 69 As an atherosclerotic plaque matures, it is commonly invaded by: A. Elastic lamellae | back 69 C. Fibrous tissue |
front 70 Advanced atherosclerotic plaques frequently become: A. Necrotic | back 70 D. Calcified |
front 71 Local muscular spasm of a coronary artery containing plaque may precipitate: A. Primary fibrinolysis | back 71 B. Secondary thrombosis coronary spasm → narrowed lumen → plaque surface/endothelium gets disrupted → platelets stick → clot forms |
front 72 Immediately after sudden occlusion of a large coronary artery, which vessels dilate first? A. Small anastomoses | back 72 A. Small anastomoses |
front 73 After acute coronary occlusion, collateral flow typically begins to rise and often doubles by: A. 12 hours | back 73 C. Days 2 to 3 |
front 74 With progressive collateral development after coronary occlusion, flow often becomes normal or nearly normal within about: A. 24 hours | back 74 B. 1 month |
front 75 Immediately after acute coronary occlusion, myocardium with essentially no effective perfusion is said to be: A. Stunned | back 75 D. Infarcted |
front 76 Soon after infarction begins, the area may become overfilled with stagnant blood because of collateral seepage plus local vessel: A. Dilation | back 76 A. Dilation |
front 77 As infarcted fibers consume the last available oxygen, hemoglobin in the area becomes: A. Oxidized | back 77 C. Deoxygenated |
front 78 Grossly, an early infarcted region often appears: A. Pale-white, collapsed vessels | back 78 B. Bluish-brown, engorged vessels |
front 79 When blood flow is compromised, myocardial injury usually begins in the: A. Epicardial region | back 79 D. Subendocardial region |
front 80 Once ischemic injury begins in the ventricular wall, it typically spreads: A. Toward the atria | back 80 C. Toward the epicardium |
front 81 After acute coronary occlusion, overall cardiac output often falls more than expected because of: A. Electrical alternans | back 81 B. Systolic stretch
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front 82 In systolic stretch, the ischemic ventricular segment is forced: A. Inward during systole | back 82 D. Outward during systole |
front 83 Which statement best describes systolic stretch? A. Infarcted muscle contracts too forcefully | back 83 C. Nonfunctional wall bulges outward |
front 84 A 72-year-old man has a massive anterior MI. Cardiogenic shock becomes highly likely when approximately what fraction of the left ventricle is infarcted? A. More than 20% | back 84 C. More than 40% |
front 85 Once cardiogenic shock develops after MI, mortality is approximately: A. Over 70% | back 85 A. Over 70% |
front 86 When the infarcted heart fails to pump blood forward, blood is primarily: A. Diluted in capillaries | back 86 B. Dammed in atria and veins |
front 87 In the days after a large infarction, venous damming often worsens because diminished renal perfusion causes: A. Osmotic diuresis | back 87 C. Reduced urine excretion |
front 88 Failure of the kidneys to excrete enough urine after severe MI most directly predisposes to: A. Acute pulmonary edema | back 88 A. Acute pulmonary edema |
front 89 After the first pulmonary symptoms from this post-MI fluid retention appear, death may occur within: A. Several weeks | back 89 B. A few hours |
front 90 Ventricular fibrillation is especially likely after: A. Small subendocardial infarcts | back 90 C. Large myocardial infarctions |
front 91 The first especially dangerous period for post-infarction fibrillation is approximately: A. 10 minutes after infarction | back 91 A. 10 minutes after infarction |
front 92 After a short safer interval, a second dangerous period for fibrillation begins about: A. 10 minutes later | back 92 B. 1 hour later |
front 93 Which Elevated extracellular ion increases myocardial irritability and promotes fibrillation after infarction? A. Sodium | back 93 D. Potassium |
front 94 Ischemic myocardium promotes fibrillation partly because it may fail to completely: A. Depolarize | back 94 B. Repolarize Simple idea:
So they fail to fully repolarize Why that causes fibrillation
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front 95 When ischemic muscle fails to fully recover electrically after a beat, its external surface remains relatively: A. Positive | back 95 C. Negative |
front 96 Which autonomic response after massive infarction further increases the risk of fibrillation? A. Vagal withdrawal | back 96 D. Powerful sympathetic reflexes Massive MI → strong sympathetic activation → ↑ heart irritability/automaticity → ↑ risk of ventricular fibrillation |
front 97 After MI, marked ventricular dilation promotes fibrillation mainly by: A. Shortening all conduction loops | back 97 C. Prolonging reentry pathways |
front 98 A nonfunctional ischemic ventricle dilates, allowing impulses to re-enter partly recovered myocardium. This initiates a: A. Wenckebach sequence | back 98 B. Circus movement cycle Impulse loops around → re-excites heart tissue → rapid abnormal rhythm |
front 99 A patient collapses several days after transmural MI when the ventricular free wall ruptures. The immediate lethal event is usually: A. Aortic dissection | back 99 D. Cardiac tamponade Free wall rupture → blood around heart → heart gets squeezed → cardiac tamponade |
front 100 In cardiac tamponade after ventricular rupture, blood most directly cannot flow into the: A. Left ventricle | back 100 B. Right atrium |
front 101 Death in acute tamponade occurs because cardiac output suddenly: A. Increases excessively | back 101 C. Decreases sharply |
front 102 After infarction, necrotic myocardium is gradually replaced by: A. Granulation myocardium | back 102 D. Fibrous scar tissue |
front 103 Surviving normal myocardium compensates after infarction mainly by: A. Atrophy | back 103 C. Hypertrophy |
front 104 Because of scar formation plus compensatory hypertrophy, cardiac function may recover: A. Only if no necrosis occurred | back 104 B. Partially or almost completely |
front 105 During early recovery from MI, excessive cardiac activity can worsen ischemia because normal vessels dilate and divert blood away from ischemic tissue. This is called: A. Reverse splitting | back 105 C. Coronary steal |
front 106 Coronary steal worsens ischemia mainly because blood preferentially flows through: A. Fibrotic infarct tissue | back 106 B. Dilated normal musculature |
front 107 The concept of coronary steal explains why the recovering infarcted heart benefits from: A. Vigorous exercise | back 107 D. Rest |
front 108 After MI, pumping ability is more often permanently: A. Increased above normal | back 108 C. Decreased below healthy levels |
front 109 The ability of the normal heart to increase output 300 to 400% above resting requirement is called: A. Ejection reserve | back 109 B. Cardiac reserve |
front 110 Which set best represents the pain-producing substances released by ischemic myocardium? A. Glucose, insulin, glycogen, pyruvate | back 110 C. Lactate, histamine, kinins, enzymes |
front 111 These ischemic products accumulate mainly because coronary blood flow is: A. Too slow for clearance | back 111 A. Too slow for clearance |
front 112 Lactic acid, histamine, kinins, and proteolytic enzymes cause cardiac pain mainly by stimulating: A. Baroreceptors in carotid sinus | back 112 D. Pain endings in myocardium |
front 113 Progressive cardiac pain from ongoing coronary constriction is called: A. Pleuritic syndrome | back 113 B. Angina pectoris |
front 114 Typical anginal pain is usually first felt beneath the: A. Upper sternum | back 114 A. Upper sternum |
front 115 Classic referred pain of angina often involves the: A. Right leg and groin | back 115 C. Left arm and shoulder |
front 116 Anginal pain may also radiate to the: A. Right jaw and axilla | back 116 D. Neck and face |
front 117 A patient with chronic stable angina most often develops pain during: A. Deep sleep or physical stress | back 117 B. Exercise or emotional stress |
front 118 Cold weather or a large meal can worsen angina mainly by increasing cardiac: A. Workload | back 118 A. Workload |
front 119 For an acute anginal attack, the best immediate drug is: A. Metoprolol | back 119 D. Nitroglycerin |
front 120 Nitroglycerin belongs to which drug class? A. Beta blockers | back 120 C. Nitrate vasodilators |
front 121 Which drug may help chronic stable angina? A. Digoxin | back 121 B. Ranolazine |
front 122 During stress, beta blockers reduce angina mainly by lowering myocardial: A. Glucose uptake | back 122 D. Oxygen demand |
front 123 Harvesting a leg vein and grafting from the aorta to a coronary artery beyond a blockage describes: A. CABG | back 123 A. CABG |
front 124 The usual symptomatic result of CABG is: A. Immediate infarct extension | back 124 B. Relief in most patients |
front 125 A balloon-tipped catheter or stent used to open a partially blocked coronary artery is: A. Coronary endarterectomy | back 125 C. Coronary angioplasty |
front 126 In exercising muscle, deficiency of what triggers vasodilator release? A. Carbon dioxide | back 126 B. Oxygen |
front 127 Which statement best describes emotionally triggered angina? A. Pain follows vagal bradycardia | back 127 D. Stress can transiently constrict coronaries |
front 128 The trigger for angina is best described as: A. Coronary flow exceeding demand | back 128 B. Cardiac load exceeding coronary flow |
front 129 A patient describes chest pain as “hot, pressing, and constricting,” provoked by exertion and stress. The best diagnosis is: A. Acute pericarditis | back 129 C. Angina pectoris |
front 130 Ischemia stimulates growth of: A. Myocytes | back 130 B. Fibroblasts |