ABCP PERFUSION BASIC SCIENCE REVIEW EXAM 150 QUESTIONS AND
CORRECT ANSWERS WITH RATIONALES COVERING THE RECENT
TESTED QUESTIONS PERFECT FOR A+ GRADE
1. What is the primary function of hemoglobin?
A. Maintain blood pressure
B. Transport oxygen
C. Clot blood
D. Regulate pH
Rationale: Hemoglobin binds oxygen in the lungs and carries it to tissues.
2. Which molecule is the primary energy source for cardiac myocytes?
A. Glucose
B. Glycogen
C. Fatty acids
D. Amino acids
Rationale: Under normal conditions, the heart primarily metabolizes fatty acids for ATP production.
3. During cardiopulmonary bypass, systemic vascular resistance is primarily influenced by:
A. Hemoglobin
B. Heart rate
C. Vasomotor tone
D. Blood glucose
Rationale: Vasomotor tone of the arteries and arterioles determines systemic vascular resistance.
4. Which electrolyte is most critical for myocardial contractility?
A. Sodium
B. Calcium
C. Potassium
D. Magnesium
Rationale: Calcium influx triggers myocardial contraction through actin-myosin cross-bridge formation.
5. Which phase of the cardiac action potential corresponds to rapid depolarization?
,A. Phase 1
B. Phase 0
C. Phase 2
D. Phase 3
Rationale: Phase 0 represents rapid influx of sodium ions, causing depolarization of cardiac cells.
6. What is the normal range for arterial oxygen tension (PaO₂) in adults?
A. 30–50 mmHg
B. 80–100 mmHg
C. 110–130 mmHg
D. 50–70 mmHg
Rationale: Normal PaO₂ in arterial blood is 80–100 mmHg.
7. Which component of blood is primarily responsible for clotting?
A. Red blood cells
B. Plasma
C. Platelets
D. White blood cells
Rationale: Platelets aggregate and facilitate coagulation to prevent bleeding.
8. What is the major buffer system in blood?
A. Phosphate
B. Protein
C. Bicarbonate
D. Ammonia
Rationale: The bicarbonate-carbonic acid system maintains blood pH near 7.4.
9. Which gas is most responsible for regulating ventilation?
A. Oxygen
B. Carbon dioxide
C. Nitrogen
D. Helium
Rationale: CO₂ levels primarily drive ventilation via chemoreceptor feedback.
,10. What is the normal range for potassium in plasma?
A. 1.5–2.5 mEq/L
B. 3.0–4.0 mEq/L
C. 3.5–5.0 mEq/L
D. 5.5–6.5 mEq/L
Rationale: Normal serum potassium is 3.5–5.0 mEq/L; deviations can cause arrhythmias.
11. Which ion is responsible for the plateau phase (Phase 2) of cardiac action potential?
A. Sodium
B. Potassium
C. Calcium
D. Chloride
Rationale: Calcium influx balances potassium efflux during Phase 2, creating the plateau.
12. Which lab value indicates adequate anticoagulation with heparin during bypass?
A. INR
B. PT
C. ACT (Activated Clotting Time)
D. Platelet count
Rationale: ACT is monitored to ensure proper heparinization during cardiopulmonary bypass.
13. Which organ is primarily responsible for lactate clearance?
A. Kidney
B. Liver
C. Lungs
D. Spleen
Rationale: The liver metabolizes lactate via gluconeogenesis and the Cori cycle.
14. Which part of the heart has the highest oxygen extraction?
A. Right atrium
B. Right ventricle
C. Left ventricle
D. Pulmonary artery
Rationale: Left ventricle has the highest oxygen demand due to systemic workload.
, 15. Which factor shifts the oxygen-hemoglobin dissociation curve to the right?
A. Decreased temperature
B. Increased pH
C. Increased CO₂ or H⁺
D. Decreased 2,3-DPG
Rationale: High CO₂, H⁺, or temperature lowers hemoglobin affinity for oxygen, enhancing tissue
delivery.
16. Which is a common cause of metabolic acidosis during bypass?
A. Hyperventilation
B. Lactic acid accumulation
C. Hypokalemia
D. Alkalosis
Rationale: Tissue hypoperfusion during bypass can cause lactate buildup, leading to metabolic acidosis.
17. Which type of cardioplegia is commonly used to arrest the heart during surgery?
A. Hypertonic saline
B. High-potassium solution
C. Hypocalcemic solution
D. Low-glucose solution
Rationale: High-potassium cardioplegia depolarizes the myocardium, temporarily arresting the heart.
18. During hypothermic bypass, metabolic rate decreases approximately by:
A. 10% per 1°C decrease
B. 7% per 1°C decrease
C. 15% per 1°C decrease
D. 5% per 1°C decrease
Rationale: Cooling reduces oxygen demand by ~7% per °C drop in body temperature.
19. What is the normal hematocrit range for adults?
A. 20–30%
B. 38–45%
CORRECT ANSWERS WITH RATIONALES COVERING THE RECENT
TESTED QUESTIONS PERFECT FOR A+ GRADE
1. What is the primary function of hemoglobin?
A. Maintain blood pressure
B. Transport oxygen
C. Clot blood
D. Regulate pH
Rationale: Hemoglobin binds oxygen in the lungs and carries it to tissues.
2. Which molecule is the primary energy source for cardiac myocytes?
A. Glucose
B. Glycogen
C. Fatty acids
D. Amino acids
Rationale: Under normal conditions, the heart primarily metabolizes fatty acids for ATP production.
3. During cardiopulmonary bypass, systemic vascular resistance is primarily influenced by:
A. Hemoglobin
B. Heart rate
C. Vasomotor tone
D. Blood glucose
Rationale: Vasomotor tone of the arteries and arterioles determines systemic vascular resistance.
4. Which electrolyte is most critical for myocardial contractility?
A. Sodium
B. Calcium
C. Potassium
D. Magnesium
Rationale: Calcium influx triggers myocardial contraction through actin-myosin cross-bridge formation.
5. Which phase of the cardiac action potential corresponds to rapid depolarization?
,A. Phase 1
B. Phase 0
C. Phase 2
D. Phase 3
Rationale: Phase 0 represents rapid influx of sodium ions, causing depolarization of cardiac cells.
6. What is the normal range for arterial oxygen tension (PaO₂) in adults?
A. 30–50 mmHg
B. 80–100 mmHg
C. 110–130 mmHg
D. 50–70 mmHg
Rationale: Normal PaO₂ in arterial blood is 80–100 mmHg.
7. Which component of blood is primarily responsible for clotting?
A. Red blood cells
B. Plasma
C. Platelets
D. White blood cells
Rationale: Platelets aggregate and facilitate coagulation to prevent bleeding.
8. What is the major buffer system in blood?
A. Phosphate
B. Protein
C. Bicarbonate
D. Ammonia
Rationale: The bicarbonate-carbonic acid system maintains blood pH near 7.4.
9. Which gas is most responsible for regulating ventilation?
A. Oxygen
B. Carbon dioxide
C. Nitrogen
D. Helium
Rationale: CO₂ levels primarily drive ventilation via chemoreceptor feedback.
,10. What is the normal range for potassium in plasma?
A. 1.5–2.5 mEq/L
B. 3.0–4.0 mEq/L
C. 3.5–5.0 mEq/L
D. 5.5–6.5 mEq/L
Rationale: Normal serum potassium is 3.5–5.0 mEq/L; deviations can cause arrhythmias.
11. Which ion is responsible for the plateau phase (Phase 2) of cardiac action potential?
A. Sodium
B. Potassium
C. Calcium
D. Chloride
Rationale: Calcium influx balances potassium efflux during Phase 2, creating the plateau.
12. Which lab value indicates adequate anticoagulation with heparin during bypass?
A. INR
B. PT
C. ACT (Activated Clotting Time)
D. Platelet count
Rationale: ACT is monitored to ensure proper heparinization during cardiopulmonary bypass.
13. Which organ is primarily responsible for lactate clearance?
A. Kidney
B. Liver
C. Lungs
D. Spleen
Rationale: The liver metabolizes lactate via gluconeogenesis and the Cori cycle.
14. Which part of the heart has the highest oxygen extraction?
A. Right atrium
B. Right ventricle
C. Left ventricle
D. Pulmonary artery
Rationale: Left ventricle has the highest oxygen demand due to systemic workload.
, 15. Which factor shifts the oxygen-hemoglobin dissociation curve to the right?
A. Decreased temperature
B. Increased pH
C. Increased CO₂ or H⁺
D. Decreased 2,3-DPG
Rationale: High CO₂, H⁺, or temperature lowers hemoglobin affinity for oxygen, enhancing tissue
delivery.
16. Which is a common cause of metabolic acidosis during bypass?
A. Hyperventilation
B. Lactic acid accumulation
C. Hypokalemia
D. Alkalosis
Rationale: Tissue hypoperfusion during bypass can cause lactate buildup, leading to metabolic acidosis.
17. Which type of cardioplegia is commonly used to arrest the heart during surgery?
A. Hypertonic saline
B. High-potassium solution
C. Hypocalcemic solution
D. Low-glucose solution
Rationale: High-potassium cardioplegia depolarizes the myocardium, temporarily arresting the heart.
18. During hypothermic bypass, metabolic rate decreases approximately by:
A. 10% per 1°C decrease
B. 7% per 1°C decrease
C. 15% per 1°C decrease
D. 5% per 1°C decrease
Rationale: Cooling reduces oxygen demand by ~7% per °C drop in body temperature.
19. What is the normal hematocrit range for adults?
A. 20–30%
B. 38–45%
