521
Advanced
Pathophysiology
COMPLETED EXAM
2024
,1. A patient with chronic obstructive pulmonary disease (COPD) has
a low arterial oxygen level and a high carbon dioxide level. What is
the most likely cause of this condition?
a) Hypoventilation
b) Hyperventilation
c) Respiratory acidosis*
d) Respiratory alkalosis
Rationale: Hypoventilation leads to increased carbon dioxide
retention and decreased oxygen exchange, resulting in respiratory
acidosis. Hyperventilation causes the opposite effects, resulting in
respiratory alkalosis. COPD is a chronic condition that impairs the
ability to exhale air, causing hypoventilation.
2. A patient with diabetes mellitus has developed diabetic
ketoacidosis (DKA). What are the main metabolic disturbances that
occur in DKA?
a) Hyperglycemia, ketonemia, and metabolic acidosis*
b) Hyperglycemia, ketonuria, and metabolic alkalosis
c) Hypoglycemia, ketonemia, and metabolic acidosis
d) Hypoglycemia, ketonuria, and metabolic alkalosis
Rationale: DKA is a serious complication of diabetes mellitus that
occurs when the body cannot use glucose as a fuel source due to
insulin deficiency or resistance. The body then breaks down fat for
energy, producing ketones as a byproduct. Ketones are acidic and
can accumulate in the blood, causing ketonemia and metabolic
acidosis. Hyperglycemia is also present due to the lack of insulin
action on glucose uptake. Ketonuria is the excretion of ketones in
the urine, which can be detected by urine dipstick tests.
3. A patient with hypertension has been prescribed a beta-blocker
medication to lower their blood pressure. How does this
medication work?
a) It blocks the action of angiotensin II on the blood vessels, causing
vasodilation
,b) It blocks the action of aldosterone on the kidneys, causing
sodium and water excretion
c) It blocks the action of epinephrine and norepinephrine on the
heart and blood vessels, causing decreased cardiac output and
peripheral resistance*
d) It blocks the action of renin on the liver, causing decreased
angiotensinogen production
Rationale: Beta-blockers are a class of drugs that inhibit the effects
of epinephrine and norepinephrine, which are catecholamines that
stimulate the beta-adrenergic receptors on the heart and blood
vessels. By blocking these receptors, beta-blockers reduce the heart
rate, contractility, and conduction velocity, as well as the
vasoconstriction of the blood vessels. This results in lower cardiac
output and peripheral resistance, which are the main determinants
of blood pressure.
4. A patient with rheumatoid arthritis has joint inflammation, pain,
stiffness, and deformity. What is the underlying pathophysiological
mechanism of this disease?
a) Autoimmune attack on the synovial membrane of the joints*
b) Degenerative wear and tear of the articular cartilage of the joints
c) Infectious invasion of the synovial fluid of the joints
d) Metabolic accumulation of uric acid crystals in the joints
Rationale: Rheumatoid arthritis is an autoimmune disease that
causes chronic inflammation of the synovial membrane of the
joints. The synovial membrane is a thin layer of tissue that lines the
joint cavity and produces synovial fluid, which lubricates and
nourishes the joint. In rheumatoid arthritis, the immune system
mistakenly attacks the synovial membrane, causing it to become
thickened and inflamed. This leads to pain, stiffness, swelling, and
erosion of the joint structures.
5. A patient with cystic fibrosis has recurrent pulmonary infections,
chronic cough, and thick mucus production. What is the genetic
defect that causes this disease?
, a) A mutation in the CFTR gene that encodes a chloride channel
protein*
b) A mutation in the SLC26A4 gene that encodes a sulfate
transporter protein
c) A mutation in the ABCA3 gene that encodes a surfactant protein
d) A mutation in the SPINK1 gene that encodes a pancreatic
secretory trypsin inhibitor protein
Rationale: Cystic fibrosis is an autosomal recessive disease that
affects various organs, especially the lungs and pancreas. It is
caused by a mutation in the CFTR gene that encodes a chloride
channel protein that regulates fluid and electrolyte balance across
epithelial cells. The mutation impairs or abolishes the function of
this protein, leading to reduced chloride secretion and increased
sodium absorption by epithelial cells. This results in thickened
mucus secretion that obstructs the airways and the pancreatic
ducts, causing pulmonary infections, chronic cough, and pancreatic
insufficiency.
6. A patient with anemia has a low hemoglobin level and a low
hematocrit. What are the possible causes of this condition?
a) Blood loss, hemolysis, or decreased erythropoiesis*
b) Blood transfusion, polycythemia, or increased erythropoiesis
c) Dehydration, thrombosis, or decreased leukopoiesis
d) Fluid overload, hemorrhage, or increased leukopoiesis
Rationale: Anemia is a condition that occurs when the hemoglobin
level or the hematocrit is lower than normal. Hemoglobin is a
protein that carries oxygen in the red blood cells (RBCs), and
hematocrit is the percentage of blood volume that is occupied by
RBCs. The possible causes of anemia are blood loss, hemolysis, or
decreased erythropoiesis. Blood loss can occur due to trauma,
surgery, menstruation, or gastrointestinal bleeding. Hemolysis is
the destruction of RBCs due to immune reactions, infections,
toxins, or inherited defects. Decreased erythropoiesis is the
reduced production of RBCs due to bone marrow failure, nutritional
deficiencies, chronic diseases, or hormonal imbalances.