SCI 221 Exam 3 V1 | SCI 221 Human
Physiology with Intervention Skill-Based
(ISB) Experiential Learning | Q&A with
Rationale (SCI221 Exam 3) | Nightingale
College
1. Which of the following hormones is primarily responsible for increasing the permeability of
the collecting duct to water in the nephron?
A. Antidiuretic Hormone (ADH)
B. Aldosterone
C. Atrial Natriuretic Peptide (ANP)
D. Parathyroid Hormone (PTH)
Correct Answer: A
Rationale: Antidiuretic Hormone, also known as vasopressin, acts on the V2 receptors of
the collecting duct to insert aquaporins into the apical membrane. This physiological
process allows for significant water reabsorption back into the bloodstream to concentrate
the urine. Without sufficient ADH, the collecting duct remains relatively impermeable to
water, leading to dilute urine output.
2. During the depolarization phase of an action potential in a neuron, which ion movement is
predominantly occurring?
A. Potassium ions moving out of the cell
,B. Chloride ions moving into the cell
C. Sodium ions moving into the cell
D. Calcium ions moving out of the cell
Correct Answer: C
Rationale: Depolarization is characterized by the rapid opening of voltage-gated sodium
channels, allowing sodium to rush into the intracellular fluid along its electrochemical
gradient. This influx of positive charge shifts the membrane potential from a negative
resting state toward a positive value. This event is a critical component of signal
propagation within the nervous system.
3. A patient presents with arterial blood gas (ABG) results showing a pH of 7.25, PaCO2 of 55
mmHg, and HCO3- of 26 mEq/L. Which condition is most likely?
A. Respiratory Acidosis
B. Respiratory Alkalosis
C. Metabolic Acidosis
D. Metabolic Alkalosis
Correct Answer: A
Rationale: The pH of 7.25 indicates acidemia, while the elevated PaCO2 of 55 mmHg
demonstrates carbon dioxide retention, typically due to alveolar hypoventilation. Because
the bicarbonate level is within the normal range, this represents an uncompensated
,respiratory acidosis. Clinical intervention would focus on improving ventilation to blow off
excess CO2.
4. What is the primary function of Type II alveolar cells in the lungs?
A. Facilitating rapid gas exchange
B. Phagocytosis of inhaled pathogens
C. Structural support of the alveolar wall
D. Secretory production of surfactant
Correct Answer: D
Rationale: Type II alveolar cells are cuboidal epithelial cells responsible for synthesizing
and secreting pulmonary surfactant. This substance reduces surface tension within the
alveoli, preventing their collapse during expiration and decreasing the work of breathing. A
deficiency in this surfactant is the primary cause of respiratory distress syndrome in
premature infants.
5. In the Renin-Angiotensin-Aldosterone System (RAAS), which enzyme is responsible for
converting Angiotensin I to Angiotensin II?
A. Renin
B. Erythropoietin
C. Aldosterone Synthase
D. Angiotensin-Converting Enzyme (ACE)
, Correct Answer: D
Rationale: Angiotensin-Converting Enzyme is primarily located in the vascular
endothelium of the lungs and kidneys. It cleaves two amino acids from Angiotensin I to
form the potent vasoconstrictor Angiotensin II. Understanding this pathway is essential as
ACE inhibitors are common pharmacological interventions for hypertension.
6. Which portion of the nephron is responsible for the majority of glucose and amino acid
reabsorption?
A. Distal Convoluted Tubule (DCT)
B. Descending Loop of Henle
C. Proximal Convoluted Tubule (PCT)
D. Ascending Loop of Henle
Correct Answer: C
Rationale: The Proximal Convoluted Tubule is the main site for nutrient reabsorption,
reclaiming nearly 100% of filtered glucose and amino acids via secondary active transport.
This process utilizes sodium-linked symporters located on the brush border of the tubular
cells. If blood glucose levels exceed the renal threshold, these transporters become
saturated, resulting in glycosuria.
7. Which hormone, secreted by the anterior pituitary, stimulates the production of cortisol by
the adrenal cortex?
A. Growth Hormone (GH)
Physiology with Intervention Skill-Based
(ISB) Experiential Learning | Q&A with
Rationale (SCI221 Exam 3) | Nightingale
College
1. Which of the following hormones is primarily responsible for increasing the permeability of
the collecting duct to water in the nephron?
A. Antidiuretic Hormone (ADH)
B. Aldosterone
C. Atrial Natriuretic Peptide (ANP)
D. Parathyroid Hormone (PTH)
Correct Answer: A
Rationale: Antidiuretic Hormone, also known as vasopressin, acts on the V2 receptors of
the collecting duct to insert aquaporins into the apical membrane. This physiological
process allows for significant water reabsorption back into the bloodstream to concentrate
the urine. Without sufficient ADH, the collecting duct remains relatively impermeable to
water, leading to dilute urine output.
2. During the depolarization phase of an action potential in a neuron, which ion movement is
predominantly occurring?
A. Potassium ions moving out of the cell
,B. Chloride ions moving into the cell
C. Sodium ions moving into the cell
D. Calcium ions moving out of the cell
Correct Answer: C
Rationale: Depolarization is characterized by the rapid opening of voltage-gated sodium
channels, allowing sodium to rush into the intracellular fluid along its electrochemical
gradient. This influx of positive charge shifts the membrane potential from a negative
resting state toward a positive value. This event is a critical component of signal
propagation within the nervous system.
3. A patient presents with arterial blood gas (ABG) results showing a pH of 7.25, PaCO2 of 55
mmHg, and HCO3- of 26 mEq/L. Which condition is most likely?
A. Respiratory Acidosis
B. Respiratory Alkalosis
C. Metabolic Acidosis
D. Metabolic Alkalosis
Correct Answer: A
Rationale: The pH of 7.25 indicates acidemia, while the elevated PaCO2 of 55 mmHg
demonstrates carbon dioxide retention, typically due to alveolar hypoventilation. Because
the bicarbonate level is within the normal range, this represents an uncompensated
,respiratory acidosis. Clinical intervention would focus on improving ventilation to blow off
excess CO2.
4. What is the primary function of Type II alveolar cells in the lungs?
A. Facilitating rapid gas exchange
B. Phagocytosis of inhaled pathogens
C. Structural support of the alveolar wall
D. Secretory production of surfactant
Correct Answer: D
Rationale: Type II alveolar cells are cuboidal epithelial cells responsible for synthesizing
and secreting pulmonary surfactant. This substance reduces surface tension within the
alveoli, preventing their collapse during expiration and decreasing the work of breathing. A
deficiency in this surfactant is the primary cause of respiratory distress syndrome in
premature infants.
5. In the Renin-Angiotensin-Aldosterone System (RAAS), which enzyme is responsible for
converting Angiotensin I to Angiotensin II?
A. Renin
B. Erythropoietin
C. Aldosterone Synthase
D. Angiotensin-Converting Enzyme (ACE)
, Correct Answer: D
Rationale: Angiotensin-Converting Enzyme is primarily located in the vascular
endothelium of the lungs and kidneys. It cleaves two amino acids from Angiotensin I to
form the potent vasoconstrictor Angiotensin II. Understanding this pathway is essential as
ACE inhibitors are common pharmacological interventions for hypertension.
6. Which portion of the nephron is responsible for the majority of glucose and amino acid
reabsorption?
A. Distal Convoluted Tubule (DCT)
B. Descending Loop of Henle
C. Proximal Convoluted Tubule (PCT)
D. Ascending Loop of Henle
Correct Answer: C
Rationale: The Proximal Convoluted Tubule is the main site for nutrient reabsorption,
reclaiming nearly 100% of filtered glucose and amino acids via secondary active transport.
This process utilizes sodium-linked symporters located on the brush border of the tubular
cells. If blood glucose levels exceed the renal threshold, these transporters become
saturated, resulting in glycosuria.
7. Which hormone, secreted by the anterior pituitary, stimulates the production of cortisol by
the adrenal cortex?
A. Growth Hormone (GH)
