PNB 2265 Exam 3
Questions with Correct
Answers.
1.
Which part of the nephron is primarily responsible for filtration?
A. Loop of Henle
B. Distal convoluted tubule
C. Glomerulus
D. Collecting duct
✅ Answer: C. Glomerulus
Rationale: Filtration occurs in the glomerulus where blood pressure forces plasma
into Bowman’s capsule.
2.
What drives glomerular filtration?
A. Osmotic pressure
B. Active transport
C. Hydrostatic pressure
D. Diffusion
,✅ Answer: C. Hydrostatic pressure
Rationale: Blood pressure within glomerular capillaries pushes fluid out into the
nephron.
3.
Which substance is normally NOT found in urine?
A. Urea
B. Glucose
C. Creatinine
D. Ammonia
✅ Answer: B. Glucose
Rationale: Glucose is normally reabsorbed in the proximal tubule; its presence
suggests diabetes mellitus.
4.
The majority of water reabsorption occurs in the:
A. Distal tubule
B. Collecting duct
C. Proximal convoluted tubule
D. Loop of Henle ascending limb
✅ Answer: C. Proximal convoluted tubule
Rationale: About 65–70% of filtered water is reabsorbed here.
5.
Which hormone increases water reabsorption in the kidneys?
,A. Aldosterone
B. ADH (antidiuretic hormone)
C. ANP
D. Renin
✅ Answer: B. ADH
Rationale: ADH increases permeability of the collecting duct to water.
6.
Aldosterone primarily increases reabsorption of:
A. Potassium
B. Calcium
C. Sodium
D. Hydrogen
✅ Answer: C. Sodium
Rationale: Aldosterone promotes Na⁺ reabsorption and K⁺ excretion.
7.
The countercurrent multiplier mechanism occurs in the:
A. Glomerulus
B. Loop of Henle
C. Proximal tubule
D. Distal tubule
✅ Answer: B. Loop of Henle
Rationale: It creates a concentration gradient in the medulla.
, 8.
Which condition is characterized by low blood pH?
A. Alkalosis
B. Acidosis
C. Hyperkalemia
D. Hypoxia
✅ Answer: B. Acidosis
Rationale: Acidosis = pH < 7.35.
9.
Respiratory acidosis is caused by:
A. Hyperventilation
B. Hypoventilation
C. Kidney failure
D. Excess bicarbonate
✅ Answer: B. Hypoventilation
Rationale: CO₂ retention increases carbonic acid → lowers pH.
10.
Which buffer system is the most important in extracellular fluid?
A. Protein buffer
B. Phosphate buffer
C. Bicarbonate buffer
Questions with Correct
Answers.
1.
Which part of the nephron is primarily responsible for filtration?
A. Loop of Henle
B. Distal convoluted tubule
C. Glomerulus
D. Collecting duct
✅ Answer: C. Glomerulus
Rationale: Filtration occurs in the glomerulus where blood pressure forces plasma
into Bowman’s capsule.
2.
What drives glomerular filtration?
A. Osmotic pressure
B. Active transport
C. Hydrostatic pressure
D. Diffusion
,✅ Answer: C. Hydrostatic pressure
Rationale: Blood pressure within glomerular capillaries pushes fluid out into the
nephron.
3.
Which substance is normally NOT found in urine?
A. Urea
B. Glucose
C. Creatinine
D. Ammonia
✅ Answer: B. Glucose
Rationale: Glucose is normally reabsorbed in the proximal tubule; its presence
suggests diabetes mellitus.
4.
The majority of water reabsorption occurs in the:
A. Distal tubule
B. Collecting duct
C. Proximal convoluted tubule
D. Loop of Henle ascending limb
✅ Answer: C. Proximal convoluted tubule
Rationale: About 65–70% of filtered water is reabsorbed here.
5.
Which hormone increases water reabsorption in the kidneys?
,A. Aldosterone
B. ADH (antidiuretic hormone)
C. ANP
D. Renin
✅ Answer: B. ADH
Rationale: ADH increases permeability of the collecting duct to water.
6.
Aldosterone primarily increases reabsorption of:
A. Potassium
B. Calcium
C. Sodium
D. Hydrogen
✅ Answer: C. Sodium
Rationale: Aldosterone promotes Na⁺ reabsorption and K⁺ excretion.
7.
The countercurrent multiplier mechanism occurs in the:
A. Glomerulus
B. Loop of Henle
C. Proximal tubule
D. Distal tubule
✅ Answer: B. Loop of Henle
Rationale: It creates a concentration gradient in the medulla.
, 8.
Which condition is characterized by low blood pH?
A. Alkalosis
B. Acidosis
C. Hyperkalemia
D. Hypoxia
✅ Answer: B. Acidosis
Rationale: Acidosis = pH < 7.35.
9.
Respiratory acidosis is caused by:
A. Hyperventilation
B. Hypoventilation
C. Kidney failure
D. Excess bicarbonate
✅ Answer: B. Hypoventilation
Rationale: CO₂ retention increases carbonic acid → lowers pH.
10.
Which buffer system is the most important in extracellular fluid?
A. Protein buffer
B. Phosphate buffer
C. Bicarbonate buffer
