BIOD 152 FINAL EXAM 2026/27
QUESTIONS AND ANSWERS (VERIFIED
ANSWERS)
1. Which zone of the adrenal cortex is responsible for the synthesis of mineralocorticoids such
as aldosterone?
A. Zona reticularis
B. Zona fasciculata
C. Adrenal medulla
D. Zona glomerulosa
Answer: D
Conceptual Explanation: The adrenal cortex is divided into three zones: the outer zona
glomerulosa produces mineralocorticoids (aldosterone), the middle zona fasciculata
produces glucocorticoids (cortisol), and the inner zona reticularis produces androgens.
2. In the cardiac conduction system, which structure serves as the primary pacemaker of the
heart?
A. Atrioventricular (AV) node
B. Sinoatrial (SA) node
C. Bundle of His
,D. Purkinje fibers
Answer: B
Conceptual Explanation: The Sinoatrial (SA) node, located in the right atrium, typically
generates impulses at the fastest rate, thus acting as the primary pacemaker of the heart.
3. During the cardiac cycle, what specific event occurs during the phase of isovolumetric
contraction?
A. The atria contract to finish filling the ventricles.
B. The semilunar valves open and blood is ejected into the arteries.
C. The AV valves open and the ventricles fill with blood.
D. All four heart valves are closed and ventricular pressure rises.
Answer: D
Conceptual Explanation: Isovolumetric contraction occurs at the start of systole when the
ventricles begin to contract, increasing pressure and closing the AV valves, while the
semilunar valves remain closed, resulting in no change in volume.
4. Which of the following describes the ‘Bohr Effect’ regarding hemoglobin affinity for
oxygen?
A. Oxygen affinity decreases in response to increased PCO2 and decreased pH.
B. Oxygen affinity increases as pH increases.
C. Oxygen affinity increases when temperature rises.
, D. Oxygen affinity is unaffected by carbon dioxide levels.
Answer: A
Conceptual Explanation: The Bohr effect states that hemoglobin’s oxygen binding affinity
is inversely related to acidity and the concentration of carbon dioxide, facilitating oxygen
release in metabolically active tissues.
5. Which enzyme is responsible for the conversion of soluble fibrinogen into insoluble fibrin
threads during the final stage of blood coagulation?
A. Prothrombinase
B. Thrombin
C. Plasmin
D. Heparin
Answer: B
Conceptual Explanation: Thrombin is the active enzyme that catalyzes the transformation
of fibrinogen into fibrin, which forms the structural mesh of a blood clot.
6. What is the functional unit of the kidney where filtration, reabsorption, and secretion take
place?
A. Renal pelvis
B. Calyx
C. Glomerulus
QUESTIONS AND ANSWERS (VERIFIED
ANSWERS)
1. Which zone of the adrenal cortex is responsible for the synthesis of mineralocorticoids such
as aldosterone?
A. Zona reticularis
B. Zona fasciculata
C. Adrenal medulla
D. Zona glomerulosa
Answer: D
Conceptual Explanation: The adrenal cortex is divided into three zones: the outer zona
glomerulosa produces mineralocorticoids (aldosterone), the middle zona fasciculata
produces glucocorticoids (cortisol), and the inner zona reticularis produces androgens.
2. In the cardiac conduction system, which structure serves as the primary pacemaker of the
heart?
A. Atrioventricular (AV) node
B. Sinoatrial (SA) node
C. Bundle of His
,D. Purkinje fibers
Answer: B
Conceptual Explanation: The Sinoatrial (SA) node, located in the right atrium, typically
generates impulses at the fastest rate, thus acting as the primary pacemaker of the heart.
3. During the cardiac cycle, what specific event occurs during the phase of isovolumetric
contraction?
A. The atria contract to finish filling the ventricles.
B. The semilunar valves open and blood is ejected into the arteries.
C. The AV valves open and the ventricles fill with blood.
D. All four heart valves are closed and ventricular pressure rises.
Answer: D
Conceptual Explanation: Isovolumetric contraction occurs at the start of systole when the
ventricles begin to contract, increasing pressure and closing the AV valves, while the
semilunar valves remain closed, resulting in no change in volume.
4. Which of the following describes the ‘Bohr Effect’ regarding hemoglobin affinity for
oxygen?
A. Oxygen affinity decreases in response to increased PCO2 and decreased pH.
B. Oxygen affinity increases as pH increases.
C. Oxygen affinity increases when temperature rises.
, D. Oxygen affinity is unaffected by carbon dioxide levels.
Answer: A
Conceptual Explanation: The Bohr effect states that hemoglobin’s oxygen binding affinity
is inversely related to acidity and the concentration of carbon dioxide, facilitating oxygen
release in metabolically active tissues.
5. Which enzyme is responsible for the conversion of soluble fibrinogen into insoluble fibrin
threads during the final stage of blood coagulation?
A. Prothrombinase
B. Thrombin
C. Plasmin
D. Heparin
Answer: B
Conceptual Explanation: Thrombin is the active enzyme that catalyzes the transformation
of fibrinogen into fibrin, which forms the structural mesh of a blood clot.
6. What is the functional unit of the kidney where filtration, reabsorption, and secretion take
place?
A. Renal pelvis
B. Calyx
C. Glomerulus
