Comprehensive final BIOS 255 Exam :
Anatomy & Physiology III with Lab Latest update
2026/2027 | Chamberlain | Q&A with Rationales |
Grade A | Pass Guaranteed A+ Graded
Q1: A patient with Type A- blood receives a transfusion of Type B+ blood. Which
immunological reaction is expected?
A. No reaction due to Rh compatibility
B. Agglutination caused by anti-B antibodies in the recipient's plasma [CORRECT]
C. Hemolysis caused by anti-A antibodies in the donor's plasma
D. No reaction because ABO types are compatible
Correct Answer: B
Rationale: The correct answer is B. A patient with Type A blood has anti-B antibodies in
their plasma. When exposed to Type B blood, these antibodies bind to the B antigens on the
donor's erythrocytes, causing agglutination (clumping). This is a classic Type II
hypersensitivity reaction taught in BIOS255 hematology.
Q2: During quiet inspiration, the diaphragm contracts and moves:
A. Superiorly, decreasing thoracic volume
B. Inferiorly, increasing thoracic volume [CORRECT]
C. Laterally, decreasing intrapleural pressure
D. Anteriorly, compressing the abdominal organs
Correct Answer: B
Rationale: The correct answer is B. The diaphragm is a dome-shaped muscle. When it
contracts, it flattens and moves inferiorly toward the abdominal cavity. This increases the
vertical dimension of the thoracic cavity, which decreases intrapleural pressure (Boyle's
Law) and draws air into the lungs.
,Q3: Which of the following represents the correct partial pressure gradient for oxygen diffusion
from the alveoli into the pulmonary capillary blood?
A. Alveolar PO2 (104 mmHg) → Capillary PO2 (40 mmHg) [CORRECT]
B. Alveolar PO2 (40 mmHg) → Capillary PO2 (104 mmHg)
C. Alveolar PO2 (45 mmHg) → Capillary PO2 (40 mmHg)
D. Alveolar PO2 (104 mmHg) → Capillary PO2 (100 mmHg)
Correct Answer: A
Rationale: The correct answer is A. Gas diffusion follows the pressure gradient from high
to low pressure. The partial pressure of oxygen (PO2) in the alveoli is approximately 104
mmHg, while the PO2 in the deoxygenated blood entering the pulmonary capillaries is
about 40 mmHg. This steep gradient (60 mmHg) drives O2 into the blood.
Q4: A patient has a heart rate of 75 beats per minute and a stroke volume of 70 mL/beat. What is
the cardiac output (CO)?
A. 4.5 L/min
B. 5.25 L/min [CORRECT]
C. 6.0 L/min
D. 5250 mL/beat
Correct Answer: B
Rationale: The correct answer is B. Cardiac Output (CO) is calculated by the formula CO
= Heart Rate (HR) × Stroke Volume (SV). 75 beats/min × 70 mL/beat = 5250 mL/min,
which converts to 5.25 L/min. This is a fundamental hemodynamic calculation essential for
BIOS255.
Q5: Select all that apply: Which of the following factors will shift the oxyhemoglobin
dissociation curve to the RIGHT (decreasing hemoglobin's affinity for O2)?
A. Decreased temperature
B. Increased pH (alkalosis)
C. Increased 2,3-DPG [CORRECT]
D. Increased PCO2 [CORRECT]
E. Decreased hydrogen ion concentration
Correct Answer: C, D
Rationale: The correct answers are C and D. A right shift facilitates oxygen unloading at
the tissues (the Bohr effect). Factors causing a right shift include increased temperature,
decreased pH (acidosis), increased PCO2, and increased 2,3-diphosphoglycerate (2,3-DPG).
Decreased temperature and increased pH cause a left shift (increased affinity).
, Q6: In the transport of carbon dioxide, approximately 70% is carried in the blood as:
A. Dissolved CO2 in plasma
B. Carbaminohemoglobin bound to globin
C. Bicarbonate ions (HCO3-) in plasma [CORRECT]
D. Carbonic acid in red blood cells
Correct Answer: C
Rationale: The correct answer is C. The majority of CO2 (about 70%) is converted to
bicarbonate ions inside red blood cells via the enzyme carbonic anhydrase. The bicarbonate
then diffuses out into the plasma in exchange for chloride ions (chloride shift) to be
transported to the lungs.
Q7: A patient presents with metabolic acidosis. Which of the following compensatory
mechanisms would you expect the respiratory system to initiate?
A. Hypoventilation to retain CO2
B. Hyperventilation to blow off CO2 [CORRECT]
C. Increased reabsorption of bicarbonate by the kidneys
D. Decreased respiratory rate to increase Ph
Correct Answer: B
Rationale: The correct answer is B. In metabolic acidosis (low pH due to non-respiratory
causes like renal failure or ketoacidosis), the respiratory center is stimulated to increase
ventilation. Blowing off CO2 (an acid when dissolved as carbonic acid) reduces the
carbonic acid concentration in the blood, raising the pH back toward normal. This is
respiratory compensation.
Q8: Which layer of a blood vessel is composed primarily of smooth muscle and is responsible
for vasoconstriction and vasodilation?
A. Tunica intima
B. Tunica media [CORRECT]
C. Tunica externa (adventitia)
D. Endothelium
Correct Answer: B
Rationale: The correct answer is B. The tunica media is the middle layer of blood vessels,
composed mainly of smooth muscle and elastic fibers. Contraction and relaxation of this
smooth muscle layer control the diameter of the vessel, regulating blood flow and pressure
(resistance).
Anatomy & Physiology III with Lab Latest update
2026/2027 | Chamberlain | Q&A with Rationales |
Grade A | Pass Guaranteed A+ Graded
Q1: A patient with Type A- blood receives a transfusion of Type B+ blood. Which
immunological reaction is expected?
A. No reaction due to Rh compatibility
B. Agglutination caused by anti-B antibodies in the recipient's plasma [CORRECT]
C. Hemolysis caused by anti-A antibodies in the donor's plasma
D. No reaction because ABO types are compatible
Correct Answer: B
Rationale: The correct answer is B. A patient with Type A blood has anti-B antibodies in
their plasma. When exposed to Type B blood, these antibodies bind to the B antigens on the
donor's erythrocytes, causing agglutination (clumping). This is a classic Type II
hypersensitivity reaction taught in BIOS255 hematology.
Q2: During quiet inspiration, the diaphragm contracts and moves:
A. Superiorly, decreasing thoracic volume
B. Inferiorly, increasing thoracic volume [CORRECT]
C. Laterally, decreasing intrapleural pressure
D. Anteriorly, compressing the abdominal organs
Correct Answer: B
Rationale: The correct answer is B. The diaphragm is a dome-shaped muscle. When it
contracts, it flattens and moves inferiorly toward the abdominal cavity. This increases the
vertical dimension of the thoracic cavity, which decreases intrapleural pressure (Boyle's
Law) and draws air into the lungs.
,Q3: Which of the following represents the correct partial pressure gradient for oxygen diffusion
from the alveoli into the pulmonary capillary blood?
A. Alveolar PO2 (104 mmHg) → Capillary PO2 (40 mmHg) [CORRECT]
B. Alveolar PO2 (40 mmHg) → Capillary PO2 (104 mmHg)
C. Alveolar PO2 (45 mmHg) → Capillary PO2 (40 mmHg)
D. Alveolar PO2 (104 mmHg) → Capillary PO2 (100 mmHg)
Correct Answer: A
Rationale: The correct answer is A. Gas diffusion follows the pressure gradient from high
to low pressure. The partial pressure of oxygen (PO2) in the alveoli is approximately 104
mmHg, while the PO2 in the deoxygenated blood entering the pulmonary capillaries is
about 40 mmHg. This steep gradient (60 mmHg) drives O2 into the blood.
Q4: A patient has a heart rate of 75 beats per minute and a stroke volume of 70 mL/beat. What is
the cardiac output (CO)?
A. 4.5 L/min
B. 5.25 L/min [CORRECT]
C. 6.0 L/min
D. 5250 mL/beat
Correct Answer: B
Rationale: The correct answer is B. Cardiac Output (CO) is calculated by the formula CO
= Heart Rate (HR) × Stroke Volume (SV). 75 beats/min × 70 mL/beat = 5250 mL/min,
which converts to 5.25 L/min. This is a fundamental hemodynamic calculation essential for
BIOS255.
Q5: Select all that apply: Which of the following factors will shift the oxyhemoglobin
dissociation curve to the RIGHT (decreasing hemoglobin's affinity for O2)?
A. Decreased temperature
B. Increased pH (alkalosis)
C. Increased 2,3-DPG [CORRECT]
D. Increased PCO2 [CORRECT]
E. Decreased hydrogen ion concentration
Correct Answer: C, D
Rationale: The correct answers are C and D. A right shift facilitates oxygen unloading at
the tissues (the Bohr effect). Factors causing a right shift include increased temperature,
decreased pH (acidosis), increased PCO2, and increased 2,3-diphosphoglycerate (2,3-DPG).
Decreased temperature and increased pH cause a left shift (increased affinity).
, Q6: In the transport of carbon dioxide, approximately 70% is carried in the blood as:
A. Dissolved CO2 in plasma
B. Carbaminohemoglobin bound to globin
C. Bicarbonate ions (HCO3-) in plasma [CORRECT]
D. Carbonic acid in red blood cells
Correct Answer: C
Rationale: The correct answer is C. The majority of CO2 (about 70%) is converted to
bicarbonate ions inside red blood cells via the enzyme carbonic anhydrase. The bicarbonate
then diffuses out into the plasma in exchange for chloride ions (chloride shift) to be
transported to the lungs.
Q7: A patient presents with metabolic acidosis. Which of the following compensatory
mechanisms would you expect the respiratory system to initiate?
A. Hypoventilation to retain CO2
B. Hyperventilation to blow off CO2 [CORRECT]
C. Increased reabsorption of bicarbonate by the kidneys
D. Decreased respiratory rate to increase Ph
Correct Answer: B
Rationale: The correct answer is B. In metabolic acidosis (low pH due to non-respiratory
causes like renal failure or ketoacidosis), the respiratory center is stimulated to increase
ventilation. Blowing off CO2 (an acid when dissolved as carbonic acid) reduces the
carbonic acid concentration in the blood, raising the pH back toward normal. This is
respiratory compensation.
Q8: Which layer of a blood vessel is composed primarily of smooth muscle and is responsible
for vasoconstriction and vasodilation?
A. Tunica intima
B. Tunica media [CORRECT]
C. Tunica externa (adventitia)
D. Endothelium
Correct Answer: B
Rationale: The correct answer is B. The tunica media is the middle layer of blood vessels,
composed mainly of smooth muscle and elastic fibers. Contraction and relaxation of this
smooth muscle layer control the diameter of the vessel, regulating blood flow and pressure
(resistance).
