BIOS-255 Anatomy & Physiology III with Lab –
Comprehensive Study Guide, Original Practice
Questions & Answers, BIOS 255 Exam Prep,
Practice Exam, Anatomy and Physiology III Review,
Endocrine System, Cardiovascular System, Blood &
Immunity, Respiratory System, Digestive System,
Urinary System, Reproductive System, Metabolism,
Fluid & Electrolyte Balance, Homeostasis,
Laboratory Review & Nursing Prerequisite Exam
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 antidiuretic hormone
CORRECT ANSWER: C. Regulation of renal blood flow and glomerular
filtration rate
Rationale: The juxtaglomerular apparatus (JGA) is a specialized structure formed by the
macula densa and juxtaglomerular cells. It plays a critical role in regulating renal blood
flow and glomerular filtration rate (GFR) through the renin-angiotensin-aldosterone
system (RAAS). It does not filter plasma proteins, reabsorb glucose, or secrete ADH.
Question 2: What is the primary role of the loop of Henle in the nephron?
A. Filtration of blood
B. Reabsorption of water and solutes to concentrate urine
C. Secretion of hydrogen ions
D. Production of erythropoietin
CORRECT ANSWER: B. Reabsorption of water and solutes to concentrate urine
Rationale: The loop of Henle establishes a concentration gradient in the renal medulla
by reabsorbing water (descending limb) and solutes such as sodium and chloride
(ascending limb). This process is essential for the kidney's ability to concentrate urine.
Filtration occurs in the glomerulus, secretion occurs in the distal tubule and collecting
duct, and erythropoietin is produced by interstitial cells in the kidney.
Question 3: Which hormone directly stimulates the insertion of aquaporin-2
channels into the apical membrane of collecting duct cells?
,A. Aldosterone
B. Antidiuretic hormone
C. Atrial natriuretic peptide
D. Angiotensin II
CORRECT ANSWER: B. Antidiuretic hormone
Rationale: Antidiuretic hormone (ADH) binds to V2 receptors on principal cells in the
collecting duct, triggering a signaling cascade that results in the insertion of aquaporin-2
water channels into the apical membrane. This increases water permeability and water
reabsorption. Aldosterone regulates sodium channels, ANP promotes sodium excretion,
and Angiotensin II primarily causes vasoconstriction and aldosterone release.
Question 4: A patient is diagnosed with metabolic acidosis. Which renal
compensatory mechanism will be activated to restore acid-base balance?
A. Increased reabsorption of bicarbonate
B. Decreased secretion of hydrogen ions
C. Increased excretion of bicarbonate
D. Decreased production of ammonia
CORRECT ANSWER: A. Increased reabsorption of bicarbonate
Rationale: In metabolic acidosis, the kidneys compensate by increasing the reabsorption
of filtered bicarbonate (HCO3-) from the tubular fluid and by generating new
bicarbonate through the excretion of titratable acids and ammonium. This helps to raise
the plasma bicarbonate concentration and correct the acidosis. The other options would
worsen acidosis.
Question 5: What is the primary effect of aldosterone on the distal convoluted
tubule and collecting duct?
A. Increased water reabsorption via aquaporins
B. Increased sodium reabsorption and potassium secretion
C. Decreased sodium reabsorption and increased water excretion
D. Increased calcium reabsorption
CORRECT ANSWER: B. Increased sodium reabsorption and potassium
secretion
Rationale: Aldosterone, a mineralocorticoid produced by the adrenal cortex, acts on
principal cells to increase the expression of epithelial sodium channels (ENaC) and
Na+/K+ ATPase pumps. This leads to increased reabsorption of sodium (and water
osmotically) and increased secretion of potassium into the tubular fluid. Its primary
effect is not on aquaporins (ADH), calcium, or sodium excretion.
,Question 6: Which of the following describes the normal pathway of urine flow
from the kidney to the outside of the body?
A. Urethra → Bladder → Ureter → Kidney
B. Bladder → Urethra → Ureter → Kidney
C. Kidney → Ureter → Bladder → Urethra
D. Kidney → Urethra → Bladder → Ureter
CORRECT ANSWER: C. Kidney → Ureter → Bladder → Urethra
Rationale: Urine is produced in the kidney, then travels down the ureter to the urinary
bladder for storage. From the bladder, it is expelled through the urethra. This is the
correct anatomical pathway. The other options are anatomically incorrect.
Question 7: What is the glomerular filtration rate (GFR) approximately in a
healthy adult?
A. 1.25 mL/min
B. 125 mL/min
C. 1250 mL/min
D. 12.5 mL/min
CORRECT ANSWER: B. 125 mL/min
Rationale: The normal GFR for a healthy adult is approximately 125 mL/min or 180
L/day. This is the volume of plasma filtered by the glomeruli per minute. Options A, C,
and D are not correct values for normal GFR.
Question 8: Which of the following pressures promotes filtration at the
glomerular capillaries?
A. Colloid osmotic pressure of plasma
B. Hydrostatic pressure in Bowman's capsule
C. Glomerular capillary blood hydrostatic pressure
D. Capsular colloid osmotic pressure
CORRECT ANSWER: C. Glomerular capillary blood hydrostatic pressure
Rationale: The net filtration pressure is the sum of forces favoring filtration (glomerular
capillary hydrostatic pressure) minus forces opposing filtration (plasma colloid osmotic
pressure and Bowman's capsule hydrostatic pressure). Glomerular capillary blood
hydrostatic pressure is the primary driving force for filtration.
Question 9: A patient has a tumor that secretes excessive amounts of
parathyroid hormone (PTH). Which of the following would be expected in their
renal function?
, A. Increased calcium reabsorption and phosphate excretion
B. Decreased calcium reabsorption and increased phosphate reabsorption
C. Increased calcium excretion and decreased phosphate excretion
D. No change in calcium or phosphate handling
CORRECT ANSWER: A. Increased calcium reabsorption and phosphate
excretion
Rationale: Parathyroid hormone (PTH) acts on the kidneys to increase calcium
reabsorption in the distal convoluted tubule and decrease phosphate reabsorption
(increase phosphate excretion) in the proximal tubule. This results in hypercalcemia and
hypophosphatemia.
Question 10: What is the function of the vasa recta in the kidney?
A. To filter blood
B. To maintain the osmotic gradient in the renal medulla
C. To secrete renin
D. To reabsorb glucose
CORRECT ANSWER: B. To maintain the osmotic gradient in the renal medulla
Rationale: The vasa recta is a network of peritubular capillaries that runs parallel to the
loop of Henle. Its primary function is to maintain the medullary osmotic gradient by
acting as a countercurrent exchanger. It prevents the washout of the high solute
concentration established by the loop of Henle. It does not filter blood, secrete renin
(JGA), or reabsorb glucose (proximal tubule).
Question 11: Which structure is the site of sperm production in the male
reproductive system?
A. Seminal vesicle
B. Epididymis
C. Seminiferous tubules
D. Vas deferens
CORRECT ANSWER: C. Seminiferous tubules
Rationale: Spermatogenesis, the process of sperm production, occurs within the
seminiferous tubules of the testes. The epididymis is where sperm mature and are
stored, the vas deferens transports sperm, and the seminal vesicles produce seminal
fluid.
Question 12: Which cell type within the seminiferous tubules provides
nutrients and support to developing sperm cells?
Comprehensive Study Guide, Original Practice
Questions & Answers, BIOS 255 Exam Prep,
Practice Exam, Anatomy and Physiology III Review,
Endocrine System, Cardiovascular System, Blood &
Immunity, Respiratory System, Digestive System,
Urinary System, Reproductive System, Metabolism,
Fluid & Electrolyte Balance, Homeostasis,
Laboratory Review & Nursing Prerequisite Exam
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 antidiuretic hormone
CORRECT ANSWER: C. Regulation of renal blood flow and glomerular
filtration rate
Rationale: The juxtaglomerular apparatus (JGA) is a specialized structure formed by the
macula densa and juxtaglomerular cells. It plays a critical role in regulating renal blood
flow and glomerular filtration rate (GFR) through the renin-angiotensin-aldosterone
system (RAAS). It does not filter plasma proteins, reabsorb glucose, or secrete ADH.
Question 2: What is the primary role of the loop of Henle in the nephron?
A. Filtration of blood
B. Reabsorption of water and solutes to concentrate urine
C. Secretion of hydrogen ions
D. Production of erythropoietin
CORRECT ANSWER: B. Reabsorption of water and solutes to concentrate urine
Rationale: The loop of Henle establishes a concentration gradient in the renal medulla
by reabsorbing water (descending limb) and solutes such as sodium and chloride
(ascending limb). This process is essential for the kidney's ability to concentrate urine.
Filtration occurs in the glomerulus, secretion occurs in the distal tubule and collecting
duct, and erythropoietin is produced by interstitial cells in the kidney.
Question 3: Which hormone directly stimulates the insertion of aquaporin-2
channels into the apical membrane of collecting duct cells?
,A. Aldosterone
B. Antidiuretic hormone
C. Atrial natriuretic peptide
D. Angiotensin II
CORRECT ANSWER: B. Antidiuretic hormone
Rationale: Antidiuretic hormone (ADH) binds to V2 receptors on principal cells in the
collecting duct, triggering a signaling cascade that results in the insertion of aquaporin-2
water channels into the apical membrane. This increases water permeability and water
reabsorption. Aldosterone regulates sodium channels, ANP promotes sodium excretion,
and Angiotensin II primarily causes vasoconstriction and aldosterone release.
Question 4: A patient is diagnosed with metabolic acidosis. Which renal
compensatory mechanism will be activated to restore acid-base balance?
A. Increased reabsorption of bicarbonate
B. Decreased secretion of hydrogen ions
C. Increased excretion of bicarbonate
D. Decreased production of ammonia
CORRECT ANSWER: A. Increased reabsorption of bicarbonate
Rationale: In metabolic acidosis, the kidneys compensate by increasing the reabsorption
of filtered bicarbonate (HCO3-) from the tubular fluid and by generating new
bicarbonate through the excretion of titratable acids and ammonium. This helps to raise
the plasma bicarbonate concentration and correct the acidosis. The other options would
worsen acidosis.
Question 5: What is the primary effect of aldosterone on the distal convoluted
tubule and collecting duct?
A. Increased water reabsorption via aquaporins
B. Increased sodium reabsorption and potassium secretion
C. Decreased sodium reabsorption and increased water excretion
D. Increased calcium reabsorption
CORRECT ANSWER: B. Increased sodium reabsorption and potassium
secretion
Rationale: Aldosterone, a mineralocorticoid produced by the adrenal cortex, acts on
principal cells to increase the expression of epithelial sodium channels (ENaC) and
Na+/K+ ATPase pumps. This leads to increased reabsorption of sodium (and water
osmotically) and increased secretion of potassium into the tubular fluid. Its primary
effect is not on aquaporins (ADH), calcium, or sodium excretion.
,Question 6: Which of the following describes the normal pathway of urine flow
from the kidney to the outside of the body?
A. Urethra → Bladder → Ureter → Kidney
B. Bladder → Urethra → Ureter → Kidney
C. Kidney → Ureter → Bladder → Urethra
D. Kidney → Urethra → Bladder → Ureter
CORRECT ANSWER: C. Kidney → Ureter → Bladder → Urethra
Rationale: Urine is produced in the kidney, then travels down the ureter to the urinary
bladder for storage. From the bladder, it is expelled through the urethra. This is the
correct anatomical pathway. The other options are anatomically incorrect.
Question 7: What is the glomerular filtration rate (GFR) approximately in a
healthy adult?
A. 1.25 mL/min
B. 125 mL/min
C. 1250 mL/min
D. 12.5 mL/min
CORRECT ANSWER: B. 125 mL/min
Rationale: The normal GFR for a healthy adult is approximately 125 mL/min or 180
L/day. This is the volume of plasma filtered by the glomeruli per minute. Options A, C,
and D are not correct values for normal GFR.
Question 8: Which of the following pressures promotes filtration at the
glomerular capillaries?
A. Colloid osmotic pressure of plasma
B. Hydrostatic pressure in Bowman's capsule
C. Glomerular capillary blood hydrostatic pressure
D. Capsular colloid osmotic pressure
CORRECT ANSWER: C. Glomerular capillary blood hydrostatic pressure
Rationale: The net filtration pressure is the sum of forces favoring filtration (glomerular
capillary hydrostatic pressure) minus forces opposing filtration (plasma colloid osmotic
pressure and Bowman's capsule hydrostatic pressure). Glomerular capillary blood
hydrostatic pressure is the primary driving force for filtration.
Question 9: A patient has a tumor that secretes excessive amounts of
parathyroid hormone (PTH). Which of the following would be expected in their
renal function?
, A. Increased calcium reabsorption and phosphate excretion
B. Decreased calcium reabsorption and increased phosphate reabsorption
C. Increased calcium excretion and decreased phosphate excretion
D. No change in calcium or phosphate handling
CORRECT ANSWER: A. Increased calcium reabsorption and phosphate
excretion
Rationale: Parathyroid hormone (PTH) acts on the kidneys to increase calcium
reabsorption in the distal convoluted tubule and decrease phosphate reabsorption
(increase phosphate excretion) in the proximal tubule. This results in hypercalcemia and
hypophosphatemia.
Question 10: What is the function of the vasa recta in the kidney?
A. To filter blood
B. To maintain the osmotic gradient in the renal medulla
C. To secrete renin
D. To reabsorb glucose
CORRECT ANSWER: B. To maintain the osmotic gradient in the renal medulla
Rationale: The vasa recta is a network of peritubular capillaries that runs parallel to the
loop of Henle. Its primary function is to maintain the medullary osmotic gradient by
acting as a countercurrent exchanger. It prevents the washout of the high solute
concentration established by the loop of Henle. It does not filter blood, secrete renin
(JGA), or reabsorb glucose (proximal tubule).
Question 11: Which structure is the site of sperm production in the male
reproductive system?
A. Seminal vesicle
B. Epididymis
C. Seminiferous tubules
D. Vas deferens
CORRECT ANSWER: C. Seminiferous tubules
Rationale: Spermatogenesis, the process of sperm production, occurs within the
seminiferous tubules of the testes. The epididymis is where sperm mature and are
stored, the vas deferens transports sperm, and the seminal vesicles produce seminal
fluid.
Question 12: Which cell type within the seminiferous tubules provides
nutrients and support to developing sperm cells?
