Chamberlain University BIOS-256 Anatomy &
Physiology IV with Lab – Comprehensive Study
Guide, Original Practice Questions & Answers,
BIOS 256 Exam Preparation, A&P IV Review,
Digestive System, Metabolism & Nutrition,
Urinary System, Fluid & Electrolyte Balance,
Acid-Base Balance, Reproductive System,
Human Development, Inheritance,
Homeostasis & Laboratory Practicum
Preparation
Question 1: Which of the following best describes the primary function of the
juxtaglomerular apparatus?
A. Filtration of plasma proteins
B. Reabsorption of glucose in the proximal tubule
C. Regulation of renal blood flow and glomerular filtration rate
D. Secretion of hydrogen ions into the collecting duct
CORRECT ANSWER: C. Regulation of renal blood flow and glomerular
filtration rate
Rationale: The juxtaglomerular apparatus, located at the vascular pole of the renal
corpuscle, consists of macula densa cells and juxtaglomerular cells. Its primary role is to
regulate renal blood flow and glomerular filtration rate through the tubuloglomerular
feedback mechanism and the release of renin.
Question 2: Which hormone is primarily responsible for stimulating the
insertion of aquaporin-2 channels into the apical membrane of collecting duct
cells?
A. Aldosterone
B. Atrial natriuretic peptide
C. Antidiuretic hormone
D. Angiotensin II
CORRECT ANSWER: C. Antidiuretic hormone
Rationale: Antidiuretic hormone (ADH) binds to V2 receptors on the basolateral
membrane of collecting duct cells, initiating a cAMP-mediated signaling cascade that
leads to the phosphorylation and insertion of aquaporin-2 water channels into the apical
membrane, thereby increasing water permeability.
Question 3: In which segment of the nephron does the majority of sodium
reabsorption occur?
,A. Distal convoluted tubule
B. Collecting duct
C. Loop of Henle
D. Proximal convoluted tubule
CORRECT ANSWER: D. Proximal convoluted tubule
Rationale: The proximal convoluted tubule is responsible for reabsorbing approximately
65-70% of filtered sodium, along with water, glucose, amino acids, and other solutes.
This reabsorption is driven by the Na+/K+ ATPase pump on the basolateral membrane.
Question 4: What is the primary effect of aldosterone on the distal convoluted
tubule and collecting duct?
A. Increased water permeability
B. Increased sodium reabsorption and potassium secretion
C. Decreased calcium reabsorption
D. Increased hydrogen ion secretion
CORRECT ANSWER: B. Increased sodium reabsorption and potassium
secretion
Rationale: Aldosterone, a mineralocorticoid, acts on principal cells to increase the
expression of epithelial sodium channels (ENaC) on the apical membrane and Na+/K+
ATPase pumps on the basolateral membrane. This results in enhanced sodium
reabsorption from the tubular fluid and increased potassium secretion into it.
Question 5: Which of the following is a direct stimulus for the release of renin
from the juxtaglomerular cells?
A. Increased blood pressure in the afferent arteriole
B. Decreased sodium chloride concentration at the macula densa
C. Increased plasma volume
D. Elevated levels of atrial natriuretic peptide
CORRECT ANSWER: B. Decreased sodium chloride concentration at the
macula densa
Rationale: A decrease in sodium chloride delivery to the macula densa, signaling a low
glomerular filtration rate or low systemic volume, stimulates the juxtaglomerular cells to
release renin. This initiates the renin-angiotensin-aldosterone system to restore blood
pressure and volume.
Question 6: Which component of the respiratory system is the primary site of
gas exchange?
A. Terminal bronchioles
B. Respiratory bronchioles
C. Alveolar ducts
D. Alveoli
,CORRECT ANSWER: D. Alveoli
Rationale: Alveoli are thin-walled, highly vascularized air sacs that provide a large
surface area for the diffusion of oxygen and carbon dioxide between the air and blood.
They are the primary functional units of the lungs for gas exchange.
Question 7: The partial pressure of oxygen is highest in which of the
following?
A. Systemic arterial blood
B. Pulmonary arterial blood
C. Alveolar air
D. Systemic venous blood
CORRECT ANSWER: C. Alveolar air
Rationale: The partial pressure of oxygen (PO2) in alveolar air is approximately 100-105
mmHg, which is higher than in pulmonary arterial blood (40 mmHg). This gradient
drives the diffusion of oxygen from the alveoli into the pulmonary capillaries. Systemic
arterial blood has a PO2 of about 95-100 mmHg.
Question 8: What is the primary role of surfactant secreted by type II alveolar
cells?
A. To trap foreign particles and pathogens
B. To decrease surface tension within the alveoli
C. To facilitate the diffusion of oxygen
D. To produce mucus for the respiratory tract
CORRECT ANSWER: B. To decrease surface tension within the alveoli
Rationale: Pulmonary surfactant, primarily composed of phospholipids and proteins,
reduces the surface tension at the air-liquid interface in the alveoli. This prevents
alveolar collapse (atelectasis) during expiration and reduces the work of breathing.
Question 9: Which nerve innervates the diaphragm, the primary muscle of
inspiration?
A. Vagus nerve
B. Intercostal nerve
C. Phrenic nerve
D. Glossopharyngeal nerve
CORRECT ANSWER: C. Phrenic nerve
Rationale: The phrenic nerve arises from the cervical spinal cord (C3-C5) and provides
motor innervation to the diaphragm. Contraction of the diaphragm is the primary driver
of inspiration during quiet breathing.
Question 10: During normal quiet breathing, which of the following is true
regarding intrapleural pressure?
, A. It is always positive relative to atmospheric pressure
B. It is always negative relative to atmospheric pressure
C. It is equal to intrapulmonary pressure
D. It fluctuates between positive and negative values
CORRECT ANSWER: B. It is always negative relative to atmospheric pressure
Rationale: Intrapleural pressure is always subatmospheric (negative) due to the opposing
elastic recoil forces of the lungs and chest wall. This negative pressure is essential to
keep the lungs inflated and to facilitate airflow into the lungs during inspiration.
Question 11: Which of the following blood gas values is most indicative of
respiratory acidosis?
A. Decreased pH, increased PaCO2
B. Decreased pH, decreased PaCO2
C. Increased pH, increased PaCO2
D. Increased pH, decreased PaCO2
CORRECT ANSWER: A. Decreased pH, increased PaCO2
Rationale: Respiratory acidosis is characterized by a primary increase in arterial carbon
dioxide partial pressure (PaCO2) above 45 mmHg, resulting from hypoventilation. The
increase in carbon dioxide leads to a decrease in blood pH (acidemia) due to the
formation of carbonic acid and subsequent dissociation into hydrogen ions.
Question 12: What is the primary buffer system in the extracellular fluid?
A. Protein buffer system
B. Phosphate buffer system
C. Bicarbonate-carbonic acid buffer system
D. Hemoglobin buffer system
CORRECT ANSWER: C. Bicarbonate-carbonic acid buffer system
Rationale: The bicarbonate-carbonic acid system is the most important buffer in the
extracellular fluid. It operates as an open system, with carbonic acid being converted to
CO2 (excreted by the lungs) and bicarbonate being regulated by the kidneys, allowing
for rapid and effective buffering of pH changes.
Question 13: Which of the following describes a function of the carbonic
anhydrase enzyme in red blood cells?
A. Conversion of CO2 and H2O to carbonic acid
B. Conversion of bicarbonate to carbonic acid
C. Transport of oxygen to tissues
D. Decomposition of hemoglobin
CORRECT ANSWER: A. Conversion of CO2 and H2O to carbonic acid
Physiology IV with Lab – Comprehensive Study
Guide, Original Practice Questions & Answers,
BIOS 256 Exam Preparation, A&P IV Review,
Digestive System, Metabolism & Nutrition,
Urinary System, Fluid & Electrolyte Balance,
Acid-Base Balance, Reproductive System,
Human Development, Inheritance,
Homeostasis & Laboratory Practicum
Preparation
Question 1: Which of the following best describes the primary function of the
juxtaglomerular apparatus?
A. Filtration of plasma proteins
B. Reabsorption of glucose in the proximal tubule
C. Regulation of renal blood flow and glomerular filtration rate
D. Secretion of hydrogen ions into the collecting duct
CORRECT ANSWER: C. Regulation of renal blood flow and glomerular
filtration rate
Rationale: The juxtaglomerular apparatus, located at the vascular pole of the renal
corpuscle, consists of macula densa cells and juxtaglomerular cells. Its primary role is to
regulate renal blood flow and glomerular filtration rate through the tubuloglomerular
feedback mechanism and the release of renin.
Question 2: Which hormone is primarily responsible for stimulating the
insertion of aquaporin-2 channels into the apical membrane of collecting duct
cells?
A. Aldosterone
B. Atrial natriuretic peptide
C. Antidiuretic hormone
D. Angiotensin II
CORRECT ANSWER: C. Antidiuretic hormone
Rationale: Antidiuretic hormone (ADH) binds to V2 receptors on the basolateral
membrane of collecting duct cells, initiating a cAMP-mediated signaling cascade that
leads to the phosphorylation and insertion of aquaporin-2 water channels into the apical
membrane, thereby increasing water permeability.
Question 3: In which segment of the nephron does the majority of sodium
reabsorption occur?
,A. Distal convoluted tubule
B. Collecting duct
C. Loop of Henle
D. Proximal convoluted tubule
CORRECT ANSWER: D. Proximal convoluted tubule
Rationale: The proximal convoluted tubule is responsible for reabsorbing approximately
65-70% of filtered sodium, along with water, glucose, amino acids, and other solutes.
This reabsorption is driven by the Na+/K+ ATPase pump on the basolateral membrane.
Question 4: What is the primary effect of aldosterone on the distal convoluted
tubule and collecting duct?
A. Increased water permeability
B. Increased sodium reabsorption and potassium secretion
C. Decreased calcium reabsorption
D. Increased hydrogen ion secretion
CORRECT ANSWER: B. Increased sodium reabsorption and potassium
secretion
Rationale: Aldosterone, a mineralocorticoid, acts on principal cells to increase the
expression of epithelial sodium channels (ENaC) on the apical membrane and Na+/K+
ATPase pumps on the basolateral membrane. This results in enhanced sodium
reabsorption from the tubular fluid and increased potassium secretion into it.
Question 5: Which of the following is a direct stimulus for the release of renin
from the juxtaglomerular cells?
A. Increased blood pressure in the afferent arteriole
B. Decreased sodium chloride concentration at the macula densa
C. Increased plasma volume
D. Elevated levels of atrial natriuretic peptide
CORRECT ANSWER: B. Decreased sodium chloride concentration at the
macula densa
Rationale: A decrease in sodium chloride delivery to the macula densa, signaling a low
glomerular filtration rate or low systemic volume, stimulates the juxtaglomerular cells to
release renin. This initiates the renin-angiotensin-aldosterone system to restore blood
pressure and volume.
Question 6: Which component of the respiratory system is the primary site of
gas exchange?
A. Terminal bronchioles
B. Respiratory bronchioles
C. Alveolar ducts
D. Alveoli
,CORRECT ANSWER: D. Alveoli
Rationale: Alveoli are thin-walled, highly vascularized air sacs that provide a large
surface area for the diffusion of oxygen and carbon dioxide between the air and blood.
They are the primary functional units of the lungs for gas exchange.
Question 7: The partial pressure of oxygen is highest in which of the
following?
A. Systemic arterial blood
B. Pulmonary arterial blood
C. Alveolar air
D. Systemic venous blood
CORRECT ANSWER: C. Alveolar air
Rationale: The partial pressure of oxygen (PO2) in alveolar air is approximately 100-105
mmHg, which is higher than in pulmonary arterial blood (40 mmHg). This gradient
drives the diffusion of oxygen from the alveoli into the pulmonary capillaries. Systemic
arterial blood has a PO2 of about 95-100 mmHg.
Question 8: What is the primary role of surfactant secreted by type II alveolar
cells?
A. To trap foreign particles and pathogens
B. To decrease surface tension within the alveoli
C. To facilitate the diffusion of oxygen
D. To produce mucus for the respiratory tract
CORRECT ANSWER: B. To decrease surface tension within the alveoli
Rationale: Pulmonary surfactant, primarily composed of phospholipids and proteins,
reduces the surface tension at the air-liquid interface in the alveoli. This prevents
alveolar collapse (atelectasis) during expiration and reduces the work of breathing.
Question 9: Which nerve innervates the diaphragm, the primary muscle of
inspiration?
A. Vagus nerve
B. Intercostal nerve
C. Phrenic nerve
D. Glossopharyngeal nerve
CORRECT ANSWER: C. Phrenic nerve
Rationale: The phrenic nerve arises from the cervical spinal cord (C3-C5) and provides
motor innervation to the diaphragm. Contraction of the diaphragm is the primary driver
of inspiration during quiet breathing.
Question 10: During normal quiet breathing, which of the following is true
regarding intrapleural pressure?
, A. It is always positive relative to atmospheric pressure
B. It is always negative relative to atmospheric pressure
C. It is equal to intrapulmonary pressure
D. It fluctuates between positive and negative values
CORRECT ANSWER: B. It is always negative relative to atmospheric pressure
Rationale: Intrapleural pressure is always subatmospheric (negative) due to the opposing
elastic recoil forces of the lungs and chest wall. This negative pressure is essential to
keep the lungs inflated and to facilitate airflow into the lungs during inspiration.
Question 11: Which of the following blood gas values is most indicative of
respiratory acidosis?
A. Decreased pH, increased PaCO2
B. Decreased pH, decreased PaCO2
C. Increased pH, increased PaCO2
D. Increased pH, decreased PaCO2
CORRECT ANSWER: A. Decreased pH, increased PaCO2
Rationale: Respiratory acidosis is characterized by a primary increase in arterial carbon
dioxide partial pressure (PaCO2) above 45 mmHg, resulting from hypoventilation. The
increase in carbon dioxide leads to a decrease in blood pH (acidemia) due to the
formation of carbonic acid and subsequent dissociation into hydrogen ions.
Question 12: What is the primary buffer system in the extracellular fluid?
A. Protein buffer system
B. Phosphate buffer system
C. Bicarbonate-carbonic acid buffer system
D. Hemoglobin buffer system
CORRECT ANSWER: C. Bicarbonate-carbonic acid buffer system
Rationale: The bicarbonate-carbonic acid system is the most important buffer in the
extracellular fluid. It operates as an open system, with carbonic acid being converted to
CO2 (excreted by the lungs) and bicarbonate being regulated by the kidneys, allowing
for rapid and effective buffering of pH changes.
Question 13: Which of the following describes a function of the carbonic
anhydrase enzyme in red blood cells?
A. Conversion of CO2 and H2O to carbonic acid
B. Conversion of bicarbonate to carbonic acid
C. Transport of oxygen to tissues
D. Decomposition of hemoglobin
CORRECT ANSWER: A. Conversion of CO2 and H2O to carbonic acid
