, Question 1
Which cellular adaptation is most likely in a tissue subjected to chronic
intermittent hypoxia, leading to increased capillary density and mitochondrial
biogenesis?
A. Atrophy
B. Metaplasia
C. Hypertrophy
D. Hyperplasia
Correct Answer: C - Hypertrophy
RATIONALE
Chronic hypoxia induces compensatory hypertrophy, characterized by
increased cell size and organelle production, enhancing oxygen
utilization. Atrophy involves shrinkage, metaplasia is a change in cell
type, and hyperplasia increases cell number, not size or organelle
density.
Question 2
In a patient with septic shock, which mediator is primarily responsible for the
profound vasodilation and increased vascular permeability observed?
A. Thromboxane A2
B. Nitric oxide
C. Endothelin-1
D. Angiotensin II
Correct Answer: B - Nitric oxide
RATIONALE
Nitric oxide, induced by inflammatory cytokines, causes smooth
muscle relaxation and vasodilation, and also increases permeability.
Thromboxane A2 and endothelin-1 are vasoconstrictors, and
angiotensin II raises blood pressure.
Page 2
, Question 3
Which immunoglobulin is most effective at activating the classical
complement pathway and is also the first to appear in a primary immune
response?
A. IgA
B. IgM
C. IgG
D. IgE
Correct Answer: B - IgM
RATIONALE
IgM is a pentamer that efficiently activates complement and is the first
antibody produced in a primary response. IgG is more abundant but
appears later; IgA is mucosal; IgE is for allergic responses.
Question 4
A patient with severe diarrhea has an arterial blood gas showing pH 7.28,
PaCO2 30 mmHg, and HCO3- 14 mEq/L. What is the primary acid-base
disorder?
A. Metabolic acidosis with respiratory compensation
B. Respiratory alkalosis with metabolic compensation
C. Metabolic alkalosis with respiratory compensation
D. Respiratory acidosis with metabolic compensation
Correct Answer: A - Metabolic acidosis with respiratory
compensation
RATIONALE
Low pH and low HCO3- indicate metabolic acidosis; the low PaCO2
reflects respiratory compensation (hyperventilation). Other options do
not match the primary disturbance.
Page 3
, Question 5
Which genetic phenomenon explains why a heterozygous individual with a
mutation in the LDL receptor gene may have familial hypercholesterolemia but
with variable severity?
A. Incomplete penetrance
B. Variable expressivity
C. Anticipation
D. Genomic imprinting
Correct Answer: B - Variable expressivity
RATIONALE
Variable expressivity refers to the range of signs and symptoms that
can occur in different people with the same genetic condition.
Incomplete penetrance means some individuals do not show any
symptoms; anticipation is earlier onset in successive generations;
imprinting is parent-of-origin effects.
Question 6
Which mechanism best explains the development of diabetic ketoacidosis in a
patient with type 1 diabetes mellitus?
A. Increased insulin sensitivity leading to hypoglycemia
B. Excessive glucose uptake by cells causing osmotic diuresis
C. Absolute insulin deficiency causing lipolysis and ketogenesis
D. Autoimmune destruction of glucagon-producing cells
Correct Answer: C - Absolute insulin deficiency causing lipolysis
and ketogenesis
RATIONALE
In type 1 diabetes, absolute insulin deficiency leads to uncontrolled
lipolysis and hepatic ketogenesis, causing ketoacidosis. Increased
insulin sensitivity is not present; excessive glucose uptake is not the
issue; glucagon cells are not destroyed.
Page 4
Which cellular adaptation is most likely in a tissue subjected to chronic
intermittent hypoxia, leading to increased capillary density and mitochondrial
biogenesis?
A. Atrophy
B. Metaplasia
C. Hypertrophy
D. Hyperplasia
Correct Answer: C - Hypertrophy
RATIONALE
Chronic hypoxia induces compensatory hypertrophy, characterized by
increased cell size and organelle production, enhancing oxygen
utilization. Atrophy involves shrinkage, metaplasia is a change in cell
type, and hyperplasia increases cell number, not size or organelle
density.
Question 2
In a patient with septic shock, which mediator is primarily responsible for the
profound vasodilation and increased vascular permeability observed?
A. Thromboxane A2
B. Nitric oxide
C. Endothelin-1
D. Angiotensin II
Correct Answer: B - Nitric oxide
RATIONALE
Nitric oxide, induced by inflammatory cytokines, causes smooth
muscle relaxation and vasodilation, and also increases permeability.
Thromboxane A2 and endothelin-1 are vasoconstrictors, and
angiotensin II raises blood pressure.
Page 2
, Question 3
Which immunoglobulin is most effective at activating the classical
complement pathway and is also the first to appear in a primary immune
response?
A. IgA
B. IgM
C. IgG
D. IgE
Correct Answer: B - IgM
RATIONALE
IgM is a pentamer that efficiently activates complement and is the first
antibody produced in a primary response. IgG is more abundant but
appears later; IgA is mucosal; IgE is for allergic responses.
Question 4
A patient with severe diarrhea has an arterial blood gas showing pH 7.28,
PaCO2 30 mmHg, and HCO3- 14 mEq/L. What is the primary acid-base
disorder?
A. Metabolic acidosis with respiratory compensation
B. Respiratory alkalosis with metabolic compensation
C. Metabolic alkalosis with respiratory compensation
D. Respiratory acidosis with metabolic compensation
Correct Answer: A - Metabolic acidosis with respiratory
compensation
RATIONALE
Low pH and low HCO3- indicate metabolic acidosis; the low PaCO2
reflects respiratory compensation (hyperventilation). Other options do
not match the primary disturbance.
Page 3
, Question 5
Which genetic phenomenon explains why a heterozygous individual with a
mutation in the LDL receptor gene may have familial hypercholesterolemia but
with variable severity?
A. Incomplete penetrance
B. Variable expressivity
C. Anticipation
D. Genomic imprinting
Correct Answer: B - Variable expressivity
RATIONALE
Variable expressivity refers to the range of signs and symptoms that
can occur in different people with the same genetic condition.
Incomplete penetrance means some individuals do not show any
symptoms; anticipation is earlier onset in successive generations;
imprinting is parent-of-origin effects.
Question 6
Which mechanism best explains the development of diabetic ketoacidosis in a
patient with type 1 diabetes mellitus?
A. Increased insulin sensitivity leading to hypoglycemia
B. Excessive glucose uptake by cells causing osmotic diuresis
C. Absolute insulin deficiency causing lipolysis and ketogenesis
D. Autoimmune destruction of glucagon-producing cells
Correct Answer: C - Absolute insulin deficiency causing lipolysis
and ketogenesis
RATIONALE
In type 1 diabetes, absolute insulin deficiency leads to uncontrolled
lipolysis and hepatic ketogenesis, causing ketoacidosis. Increased
insulin sensitivity is not present; excessive glucose uptake is not the
issue; glucagon cells are not destroyed.
Page 4
