Phys 21 Flashcards

During strenuous exercise, cardiac output must usually:

A. Fall below resting levels
B. Stay near baseline
C. Increase markedly
D. Become preload-independent

During rhythmic exercise, muscle blood flow typically:

A. Remains constant each beat
B. Falls progressively
C. Rises progressively
D. Oscillates with contraction

During the contraction phase of normal exercise, muscle blood flow falls mainly because:

A. Venous PO2 rises
B. Arterioles fully dilate
C. Contracted fibers compress vessels
D. Lymphatic drainage increases

During a strong tetanic contraction, muscle blood flow can be almost abolished because of:

A. Sustained vascular compression
B. Arteriolar beta activation
C. Venous valve closure
D. Reduced metabolic demand

A sustained tetanic contraction rapidly weakens primarily because:

A. Lactic acid disappears
B. Blood flow is nearly stopped
C. Sympathetic tone is lost
D. Calcium entry is blocked

At rest, many skeletal muscle capillaries:

A. Have maximal flow
B. Are structurally collapsed
C. Carry little or no flow
D. Only drain venous blood

During exercise, effective muscle capillary surface area usually increases by about:

A. 25%
B. 50%
C. Two- to threefold
D. Five- to sixfold

A fall in interstitial oxygen concentration in active muscle has what direct vascular effect?

A. Local arteriolar vasodilation
B. Local venular constriction
C. Capillary sphincter closure
D. Sympathetic alpha activation

Which local change most strongly enhances muscle blood flow during exercise?

A. Increased tissue oxygen
B. Decreased tissue oxygen
C. Decreased carbon dioxide
D. Increased venous pressure

Which set best sustains exercise hyperemia in active muscle?

A. K+, ATP, lactate, CO2
B. Calcium, renin, serotonin, ADH
C. Albumin, chloride, bicarbonate, urea
D. Histamine, bradykinin, angiotensin, insulin

Sympathetic vasoconstrictor nerve endings in muscle chiefly release:

A. Epinephrine
B. Dopamine
C. Acetylcholine
D. Norepinephrine

Maximal sympathetic stimulation of skeletal muscle vessels can reduce blood flow to about:

A. One half to one third
B. Three fourths to full
C. One tenth to zero
D. Two thirds above baseline

Circulating epinephrine causes slight skeletal muscle vasodilation mainly by stimulating:

A. Alpha receptors
B. Beta receptors
C. Muscarinic receptors
D. Nicotinic receptors

Alpha vasoconstrictor receptors are excited especially by:

A. Norepinephrine
B. Epinephrine
C. ATP
D. Adenosine

Under resting conditions, the heart is normally restrained mainly by:

A. Sympathetic inhibition
B. Alpha receptor blockade
C. Parasympathetic inhibition
D. Reduced venous return

At exercise onset, the rise in heart rate and contractility occurs first because of:

A. Increased vagal discharge
B. Removal of vagal inhibition
C. Decreased adrenal output
D. Loss of beta receptors

During heavy exercise, most peripheral arterioles are:

A. Dilated, including inactive beds
B. Constricted, except active muscle
C. Unchanged throughout body
D. Collapsed by low pressure

Despite high sympathetic tone, active skeletal muscle still receives increased flow because:

A. Venous pressure exceeds arterial
B. Local metabolites override constriction
C. Capillaries generate pressure
D. Lymphatics pump arterial blood

As blood flow to active muscle rises, flow to many nonmuscular tissues:

A. Also rises equally
B. Falls because of redistribution
C. Remains unchanged
D. Becomes entirely capillary

During exercise, which two vascular beds are relatively spared from the generalized vasoconstriction affecting nonactive tissues?

A. Renal and splanchnic
B. Coronary and cerebral
C. Cutaneous and renal
D. Pulmonary and hepatic

Coronary and cerebral vessels are relatively spared during exercise mainly because they:

A. Have high alpha tone
B. Are nonessential to exercise
C. Need preserved perfusion
D. Lack local metabolites

Compared with many inactive vascular beds, coronary and cerebral circulations have relatively:

A. Poor vasoconstrictor innervation
B. Dense venous plexuses
C. High resting compliance
D. Minimal endothelial function

During exercise, sympathetic stimulation causes venous walls to:

A. Relax diffusely
B. Contract powerfully
C. Become metabolically inactive
D. Dilate in active muscle

Venoconstriction during exercise most directly increases:

A. Pulmonary vascular resistance
B. Mean systemic filling pressure
C. Left atrial compliance
D. Coronary sinus pressure

The major hemodynamic importance of exercise-induced venoconstriction is to increase:

A. Capillary hydrostatic pressure
B. Venous return and cardiac output
C. Coronary autoregulation
D. Systolic ejection time

In active skeletal muscle during exercise, arterioles are predominantly:

A. Vasoconstricted
B. Collapsed
C. Vasodilated
D. Unresponsive

In most nonactive tissues during exercise, the dominant arteriolar effect is:

A. Vasodilation
B. Vasoconstriction
C. No tone change
D. Passive collapse

The relatively modest pressure rise during massive whole-body exercise is best explained by:

A. Global vagal dominance
B. Widespread muscle vasodilation
C. Coronary vasoconstriction
D. Reduced venous return

Compared with an untrained runner, a trained marathon runner can increase cardiac output during maximal exercise:

A. Less
B. Equally
C. More
D. Not at all

Raising the entire venous return curve during exercise requires:

A. Lower MSFP, higher resistance
B. Higher MSFP, lower resistance
C. Higher RAP, higher resistance
D. Lower contractility, lower resistance

In a person with a very strong heart during heavy exercise, right atrial pressure often:

A. Rises above normal
B. Falls below normal
C. Remains fixed
D. Equals arterial pressure

The left coronary artery mainly supplies the:

A. Right ventricle and septum
B. Anterior and left lateral LV
C. Posterior RV and septum
D. Both atria equally

The right coronary artery supplies most of the right ventricle and the:

A. Anterior left ventricle
B. Lateral left ventricle
C. Posterior left ventricle
D. Apical septum only

Most venous blood from the left ventricular myocardium returns to the right atrium through the:

A. Great cardiac vein
B. Small cardiac vein
C. Coronary sinus
D. Thebesian plexus

Approximately what fraction of total coronary flow returns via the coronary sinus?

A. About 25%
B. About 50%
C. About 75%
D. About 95%

Most venous blood from the right ventricular myocardium returns directly to the right atrium through:

A. Coronary sinus tributaries
B. Small anterior cardiac veins
C. Middle cardiac veins
D. Posterior septal veins

A tiny amount of coronary venous blood enters all chambers directly through:

A. Vasa vasorum
B. Anterior cardiac veins
C. Coronary sinusoids
D. Thebesian veins

During strenuous exercise, myocardial work rises more than cardiac output because the heart also pumps against:

A. Lower venous pressure
B. Higher arterial pressure
C. Lower coronary resistance
D. Higher pulmonary compliance

A lifter performing intense arm exercise develops a marked rise in mean arterial pressure. Which pattern best explains this?

A. Local vasoconstriction, systemic dilation
B. Local dilation, systemic constriction
C. Global dilation, low venous tone
D. Global constriction, fixed venous return

In the left ventricular myocardium, coronary capillary blood flow during systole normally:

A. Decreases
B. Increases
C. Reverses
D. Plateaus

The fall in left ventricular coronary capillary flow during systole occurs mainly because:

A. Aortic pressure collapses
B. Vagal tone rises sharply
C. Myocardial contraction compresses vessels
D. Coronary sinus pressure falls

In the left ventricle, coronary capillary blood flow is greatest during:

A. Isovolumic contraction
B. Ventricular systole
C. Early ejection only
D. Diastole

Compared with most other vascular beds, left ventricular coronary flow is unusual because it:

A. Falls during systole
B. Stops during diastole
C. Ignores metabolic demand
D. Depends only on nerves

The coronary arteries on the outer surface of the heart are the:

A. Septal arteries
B. Thebesian arteries
C. Epicardial arteries
D. Subendocardial arteries

Immediately beneath the endocardium lies a plexus of:

A. Subendocardial arteries
B. Epicardial arteries
C. Atrial venules
D. Coronary sinusoids

Whenever cardiac contractile vigor increases, coronary blood flow generally:

A. Falls slightly
B. Also increases
C. Becomes fixed
D. Depends on venous return

Coronary blood flow rises almost in what relationship to myocardial oxygen consumption?

A. Inverse
B. Biphasic
C. Direct
D. Unrelated

Very low intracellular oxygen causes breakdown of ATP first to:

A. Creatine
B. ADP
C. Lactate
D. Acetylcholine

After ATP falls to ADP and then AMP, the next major breakdown product is:

A. Adenosine
B. Inosine
C. Pyruvate
D. NADH

Very low myocardial oxygen levels promote local coronary vasodilation mainly through release of:

A. Potassium
B. Bradykinin
C. Norepinephrine
D. Adenosine

The oxygen level that most strongly triggers adenosine release is:

A. Very low
B. Very high
C. Mildly high
D. Oscillating

Coronary vasodilation from adenosine is most directly a response to:

A. Increased venous pressure
B. Myocardial hypoxia
C. High arterial oxygen
D. Vagal discharge

Sympathetic stimulation of the heart generally:

A. Decreases metabolism
B. Prevents coronary dilation
C. Increases metabolism
D. Stops local control

During sympathetic activation, coronary vessels dilate mainly because increased cardiac metabolism triggers:

A. Local flow regulation
B. Direct alpha constriction
C. Thebesian drainage
D. Venous pooling

During sympathetic stimulation, coronary blood flow rises roughly in proportion to cardiac:

A. Heart rate only
B. Filling pressure
C. Venous return
D. Metabolic needs

Vagal stimulation indirectly tends to constrict coronary arteries because it:

A. Raises oxygen demand
B. Increases ventricular pressure
C. Lowers cardiac oxygen use
D. Stimulates alpha receptors

Despite that indirect effect, acetylcholine has what direct action on coronary arteries?

A. Dilates them
B. Constricts them
C. Occludes them
D. No effect

In coronary vessels, constrictor receptors are predominantly:

A. Muscarinic
B. Beta
C. Nicotinic
D. Alpha

In coronary vessels, dilator receptors are predominantly:

A. Alpha
B. Beta
C. H1
D. M2

Epicardial coronary vessels have a relative predominance of:

A. Alpha receptors
B. Beta receptors
C. M3 receptors
D. Dopamine receptors

Intramuscular coronary arteries may have a predominance of:

A. Alpha receptors
B. Nicotinic receptors
C. Beta receptors
D. Opioid receptors

The major controller of myocardial blood flow is:

A. Sympathetic tone
B. Myocardial oxygen consumption
C. Coronary venous pressure
D. Right atrial pressure

Under resting conditions, the heart obtains most of its energy from:

A. Glucose
B. Lactate
C. Ketones
D. Fatty acids

Under ischemic or anaerobic conditions, cardiac muscle must rely more on:

A. Fat oxidation
B. Anaerobic glycolysis
C. Oxidative phosphorylation
D. Beta-oxidation

During severe ischemia, chest pain is promoted partly by buildup of:

A. Uric acid
B. Carbonic acid
C. Lactic acid
D. Acetoacetate

During coronary hypoxia, which metabolite is believed to dilate coronary arterioles?

A. Adenosine
B. Acetylcholine
C. Lactate
D. Norepinephrine

Why is prolonged coronary occlusion especially dangerous after 30 minutes?

A. Coronary veins thrombose completely
B. Adenine resynthesis is very slow
C. Fibrosis is immediately complete
D. All collateral flow stops

In atherosclerosis, the first major material deposited beneath the arterial endothelium is:

A. Calcium
B. Cholesterol
C. Fibrin
D. Hemosiderin

As an atherosclerotic plaque matures, it is commonly invaded by:

A. Elastic lamellae
B. Lymphoid nodules
C. Fibrous tissue
D. Smooth clot only

Advanced atherosclerotic plaques frequently become:

A. Necrotic
B. Hemorrhagic
C. Ulcerated
D. Calcified

Local muscular spasm of a coronary artery containing plaque may precipitate:

A. Primary fibrinolysis
B. Secondary thrombosis
C. Valve rupture
D. Venous pooling

Immediately after sudden occlusion of a large coronary artery, which vessels dilate first?

A. Small anastomoses
B. Coronary veins
C. Endocardial lymphatics
D. Thebesian vessels

After acute coronary occlusion, collateral flow typically begins to rise and often doubles by:

A. 12 hours
B. Day 7
C. Days 2 to 3
D. Week 4

With progressive collateral development after coronary occlusion, flow often becomes normal or nearly normal within about:

A. 24 hours
B. 1 month
C. 3 months
D. 6 months

Immediately after acute coronary occlusion, myocardium with essentially no effective perfusion is said to be:

A. Stunned
B. Hibernating
C. Ischemic
D. Infarcted

Soon after infarction begins, the area may become overfilled with stagnant blood because of collateral seepage plus local vessel:

A. Dilation
B. Rupture
C. Collapse
D. Sclerosis

As infarcted fibers consume the last available oxygen, hemoglobin in the area becomes:

A. Oxidized
B. Alkalinized
C. Deoxygenated
D. Fragmented

Grossly, an early infarcted region often appears:

A. Pale-white, collapsed vessels
B. Bluish-brown, engorged vessels
C. Bright-red, empty vessels
D. Yellow-gray, shrunken vessels

When blood flow is compromised, myocardial injury usually begins in the:

A. Epicardial region
B. Midmyocardium
C. Papillary muscles
D. Subendocardial region

Once ischemic injury begins in the ventricular wall, it typically spreads:

A. Toward the atria
B. Toward the septum
C. Toward the epicardium
D. Toward the valves

After acute coronary occlusion, overall cardiac output often falls more than expected because of:

A. Electrical alternans
B. Systolic stretch
C. Reflex bradycardia
D. Diastolic collapse

In systolic stretch, the ischemic ventricular segment is forced:

A. Inward during systole
B. Downward in diastole
C. Clockwise with torsion
D. Outward during systole

Which statement best describes systolic stretch?

A. Infarcted muscle contracts too forcefully
B. Ischemic segment actively shortens
C. Nonfunctional wall bulges outward
D. Epicardium pulls septum inward

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%
B. More than 30%
C. More than 40%
D. More than 60%

Once cardiogenic shock develops after MI, mortality is approximately:

A. Over 70%
B. About 25%
C. About 40%
D. Under 10%

When the infarcted heart fails to pump blood forward, blood is primarily:

A. Diluted in capillaries
B. Dammed in atria and veins
C. Shunted through coronaries
D. Lost through lymphatics

In the days after a large infarction, venous damming often worsens because diminished renal perfusion causes:

A. Osmotic diuresis
B. Excess natriuresis
C. Reduced urine excretion
D. Increased aldosterone clearance

Failure of the kidneys to excrete enough urine after severe MI most directly predisposes to:

A. Acute pulmonary edema
B. Tension pneumothorax
C. Massive hemoptysis
D. Pleural fibrosis

After the first pulmonary symptoms from this post-MI fluid retention appear, death may occur within:

A. Several weeks
B. A few hours
C. Two days
D. One month

Ventricular fibrillation is especially likely after:

A. Small subendocardial infarcts
B. Right atrial stretch
C. Large myocardial infarctions
D. Isolated mitral regurgitation

The first especially dangerous period for post-infarction fibrillation is approximately:

A. 10 minutes after infarction
B. 30 minutes after infarction
C. 6 hours after infarction
D. 24 hours after infarction

After a short safer interval, a second dangerous period for fibrillation begins about:

A. 10 minutes later
B. 1 hour later
C. 12 hours later
D. 2 days later

Which Elevated extracellular ion increases myocardial irritability and promotes fibrillation after infarction?

A. Sodium
B. Calcium
C. Chloride
D. Potassium

Ischemic myocardium promotes fibrillation partly because it may fail to completely:

A. Depolarize
B. Repolarize
C. Contract
D. Relax

When ischemic muscle fails to fully recover electrically after a beat, its external surface remains relatively:

A. Positive
B. Neutral
C. Negative
D. Insulated

Which autonomic response after massive infarction further increases the risk of fibrillation?

A. Vagal withdrawal
B. Parasympathetic surge
C. Baroreceptor silence
D. Powerful sympathetic reflexes

After MI, marked ventricular dilation promotes fibrillation mainly by:

A. Shortening all conduction loops
B. Blocking AV nodal conduction
C. Prolonging reentry pathways
D. Eliminating refractory tissue

A nonfunctional ischemic ventricle dilates, allowing impulses to re-enter partly recovered myocardium. This initiates a:

A. Wenckebach sequence
B. Circus movement cycle
C. Escape rhythm focus
D. Junctional pause loop

A patient collapses several days after transmural MI when the ventricular free wall ruptures. The immediate lethal event is usually:

A. Aortic dissection
B. Pulmonary embolism
C. Tension pneumothorax
D. Cardiac tamponade

In cardiac tamponade after ventricular rupture, blood most directly cannot flow into the:

A. Left ventricle
B. Right atrium
C. Coronary sinus
D. Pulmonary veins

Death in acute tamponade occurs because cardiac output suddenly:

A. Increases excessively
B. Becomes fixed high
C. Decreases sharply
D. Equals venous return

After infarction, necrotic myocardium is gradually replaced by:

A. Granulation myocardium
B. Purulent debris
C. Elastic lamellae
D. Fibrous scar tissue

Surviving normal myocardium compensates after infarction mainly by:

A. Atrophy
B. Calcification
C. Hypertrophy
D. Fragmentation

Because of scar formation plus compensatory hypertrophy, cardiac function may recover:

A. Only if no necrosis occurred
B. Partially or almost completely
C. Only with valve replacement
D. Fully within hours

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
B. Ventricular stunning
C. Coronary steal
D. Hibernating myocardium

Coronary steal worsens ischemia mainly because blood preferentially flows through:

A. Fibrotic infarct tissue
B. Dilated normal musculature
C. Occluded epicardial arteries
D. Thebesian drainage channels

The concept of coronary steal explains why the recovering infarcted heart benefits from:

A. Vigorous exercise
B. High-dose vasodilators
C. Repeated tachycardia
D. Rest

After MI, pumping ability is more often permanently:

A. Increased above normal
B. Unchanged from baseline
C. Decreased below healthy levels
D. Limited only at night

The ability of the normal heart to increase output 300 to 400% above resting requirement is called:

A. Ejection reserve
B. Cardiac reserve
C. Coronary reserve
D. Preload reserve

Which set best represents the pain-producing substances released by ischemic myocardium?

A. Glucose, insulin, glycogen, pyruvate
B. Creatine, ADH, albumin, serotonin
C. Lactate, histamine, kinins, enzymes
D. Cholesterol, calcium, fibrin, collagen

These ischemic products accumulate mainly because coronary blood flow is:

A. Too slow for clearance
B. Entirely absent chronically
C. Rapid but turbulent
D. Preferentially venous

Lactic acid, histamine, kinins, and proteolytic enzymes cause cardiac pain mainly by stimulating:

A. Baroreceptors in carotid sinus
B. Stretch receptors in pericardium
C. Chemoreceptors in aorta
D. Pain endings in myocardium

Progressive cardiac pain from ongoing coronary constriction is called:

A. Pleuritic syndrome
B. Angina pectoris
C. Cardiac tamponade
D. Dressler syndrome

Typical anginal pain is usually first felt beneath the:

A. Upper sternum
B. Right scapula
C. Left flank
D. Lower abdomen

Classic referred pain of angina often involves the:

A. Right leg and groin
B. Epigastrium and back
C. Left arm and shoulder
D. Left hip and thigh

Anginal pain may also radiate to the:

A. Right jaw and axilla
B. Abdomen and flank
C. Back and sacrum
D. Neck and face

A patient with chronic stable angina most often develops pain during:

A. Deep sleep or physical stress
B. Exercise or emotional stress
C. Quiet sitting or physical stress
D. After urination or emotional stress

Cold weather or a large meal can worsen angina mainly by increasing cardiac:

A. Workload
B. Chronotropy alone
C. Venous capacitance
D. Oxygen extraction

For an acute anginal attack, the best immediate drug is:

A. Metoprolol
B. Lisinopril
C. Ranolazine
D. Nitroglycerin

Nitroglycerin belongs to which drug class?

A. Beta blockers
B. Calcium blockers
C. Nitrate vasodilators
D. Angiotensin blockers

Which drug may help chronic stable angina?

A. Digoxin
B. Ranolazine
C. Epinephrine
D. Mannitol

During stress, beta blockers reduce angina mainly by lowering myocardial:

A. Glucose uptake
B. Coronary spasm
C. Stroke work only
D. Oxygen demand

Harvesting a leg vein and grafting from the aorta to a coronary artery beyond a blockage describes:

A. CABG
B. Angioplasty
C. Valvuloplasty
D. Atherectomy

The usual symptomatic result of CABG is:

A. Immediate infarct extension
B. Relief in most patients
C. Permanent arrhythmia risk
D. No flow improvement

A balloon-tipped catheter or stent used to open a partially blocked coronary artery is:

A. Coronary endarterectomy
B. Aortic valvotomy
C. Coronary angioplasty
D. Ventricular remodeling

In exercising muscle, deficiency of what triggers vasodilator release?

A. Carbon dioxide
B. Oxygen
C. ATP
D. Sodium

Which statement best describes emotionally triggered angina?

A. Pain follows vagal bradycardia
B. It improves sympathetic tone
C. It reflects pleural inflammation
D. Stress can transiently constrict coronaries

The trigger for angina is best described as:

A. Coronary flow exceeding demand
B. Cardiac load exceeding coronary flow
C. Venous return exceeding preload
D. Afterload falling below baseline

A patient describes chest pain as “hot, pressing, and constricting,” provoked by exertion and stress. The best diagnosis is:

A. Acute pericarditis
B. Aortic dissection
C. Angina pectoris
D. Pulmonary embolism

Ischemia stimulates growth of:

A. Myocytes
B. Fibroblasts
C. Neutrophils
D. Endothelial valves