NUR 631/NUR631 Exam 2 V2 | Advanced
Physiology and Pathophysiology Q&A with
Rationale | Grand Canyon University
1. A patient presents with persistent hypertension and hypokalemia. Lab results show
elevated aldosterone and low renin levels. Which condition is most likely?
A. Conn Syndrome
B. Addison’s Disease
C. Cushing’s Disease
D. Pheochromocytoma
Answer: A
Rationale: Conn Syndrome, also known as primary hyperaldosteronism, is characterized
by excessive aldosterone production regardless of renin levels. This leads to increased
sodium reabsorption and potassium excretion in the kidneys. The suppressed renin levels
occur as a compensatory response to the fluid volume expansion and hypertension.
2. Which mechanism is primary in the development of Type 1 Diabetes Mellitus?
A. Insulin resistance in peripheral tissues
B. Down-regulation of insulin receptors
C. Excessive glucagon secretion from alpha cells
D. Autoimmune destruction of pancreatic beta cells
,Answer: D
Rationale: Type 1 Diabetes is primarily caused by a T-cell mediated autoimmune attack on
the insulin-producing beta cells of the pancreas. This destruction results in an absolute
insulin deficiency, requiring exogenous insulin administration. It is often associated with
specific HLA genotypes and autoantibodies such as GAD65.
3. Which part of the nephron is responsible for the majority of water and solute
reabsorption?
A. Proximal convoluted tubule
B. Loop of Henle
C. Distal convoluted tubule
D. Collecting duct
Answer: A
Rationale: The proximal convoluted tubule is the site where approximately 65 to 70
percent of filtered sodium and water are reabsorbed. It also handles the reabsorption of
glucose, amino acids, and bicarbonate. The extensive microvilli on the luminal surface of
these cells provide a large surface area for this intensive transport activity.
4. In the presence of Antidiuretic Hormone (ADH), what change occurs in the collecting duct?
A. Sodium channels are closed
B. Calcium reabsorption is inhibited
, C. Permeability to urea is decreased
D. Aquaporin-2 channels are inserted into the apical membrane
Answer: D
Rationale: ADH binds to V2 receptors on the basolateral membrane of collecting duct cells,
initiating a second messenger cascade. This cascade results in the translocation of
aquaporin-2 water channels to the apical membrane. This significantly increases the
permeability of the duct to water, allowing for the concentration of urine.
5. A patient’s ABG results show: pH 7.25, PaCO2 55 mmHg, and HCO3 26 mEq/L. This
indicates:
A. Metabolic Acidosis
B. Respiratory Alkalosis
C. Metabolic Alkalosis
D. Respiratory Acidosis
Answer: D
Rationale: A pH below 7.35 indicates acidosis, while a PaCO2 above 45 mmHg indicates a
respiratory cause. Since the bicarbonate level is within or near the normal range, it
suggests that compensation has not yet occurred or is incomplete. This pattern is classic for
acute respiratory failure or hypoventilation.
Physiology and Pathophysiology Q&A with
Rationale | Grand Canyon University
1. A patient presents with persistent hypertension and hypokalemia. Lab results show
elevated aldosterone and low renin levels. Which condition is most likely?
A. Conn Syndrome
B. Addison’s Disease
C. Cushing’s Disease
D. Pheochromocytoma
Answer: A
Rationale: Conn Syndrome, also known as primary hyperaldosteronism, is characterized
by excessive aldosterone production regardless of renin levels. This leads to increased
sodium reabsorption and potassium excretion in the kidneys. The suppressed renin levels
occur as a compensatory response to the fluid volume expansion and hypertension.
2. Which mechanism is primary in the development of Type 1 Diabetes Mellitus?
A. Insulin resistance in peripheral tissues
B. Down-regulation of insulin receptors
C. Excessive glucagon secretion from alpha cells
D. Autoimmune destruction of pancreatic beta cells
,Answer: D
Rationale: Type 1 Diabetes is primarily caused by a T-cell mediated autoimmune attack on
the insulin-producing beta cells of the pancreas. This destruction results in an absolute
insulin deficiency, requiring exogenous insulin administration. It is often associated with
specific HLA genotypes and autoantibodies such as GAD65.
3. Which part of the nephron is responsible for the majority of water and solute
reabsorption?
A. Proximal convoluted tubule
B. Loop of Henle
C. Distal convoluted tubule
D. Collecting duct
Answer: A
Rationale: The proximal convoluted tubule is the site where approximately 65 to 70
percent of filtered sodium and water are reabsorbed. It also handles the reabsorption of
glucose, amino acids, and bicarbonate. The extensive microvilli on the luminal surface of
these cells provide a large surface area for this intensive transport activity.
4. In the presence of Antidiuretic Hormone (ADH), what change occurs in the collecting duct?
A. Sodium channels are closed
B. Calcium reabsorption is inhibited
, C. Permeability to urea is decreased
D. Aquaporin-2 channels are inserted into the apical membrane
Answer: D
Rationale: ADH binds to V2 receptors on the basolateral membrane of collecting duct cells,
initiating a second messenger cascade. This cascade results in the translocation of
aquaporin-2 water channels to the apical membrane. This significantly increases the
permeability of the duct to water, allowing for the concentration of urine.
5. A patient’s ABG results show: pH 7.25, PaCO2 55 mmHg, and HCO3 26 mEq/L. This
indicates:
A. Metabolic Acidosis
B. Respiratory Alkalosis
C. Metabolic Alkalosis
D. Respiratory Acidosis
Answer: D
Rationale: A pH below 7.35 indicates acidosis, while a PaCO2 above 45 mmHg indicates a
respiratory cause. Since the bicarbonate level is within or near the normal range, it
suggests that compensation has not yet occurred or is incomplete. This pattern is classic for
acute respiratory failure or hypoventilation.
