Renal Acid-Base Regulation Practice Questions
16 free Renal Acid-Base Regulation practice questions for the Physiology. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.
Which cells in the collecting duct are mainly responsible for hydrogen ion secretion?
- A Collecting duct principal cells
- B Intercalated cells type A
- C Distal tubule macula densa cells
- D Mesangial cells
Correct answer: Intercalated cells type A
Type A intercalated cells actively secrete hydrogen ions into the tubular lumen. They play a key role in acid elimination and bicarbonate generation.
Which mechanism allows the kidney to generate new bicarbonate?
- A Glucose filtration
- B Ammonium excretion
- C Sodium reabsorption
- D Water reabsorption
Correct answer: Ammonium excretion
Ammonium excretion leads to the production of new bicarbonate ions. This process is crucial in compensating for acidosis.
Which renal response occurs during metabolic acidosis?
- A Decreased hydrogen ion secretion
- B Increased bicarbonate excretion
- C Decreased ammonium production
- D Increased hydrogen ion secretion
Correct answer: Increased hydrogen ion secretion
In metabolic acidosis, the kidney increases hydrogen ion secretion to eliminate excess acid and restore normal pH.
Which buffer system in the renal tubules helps excrete hydrogen ions?
- A Phosphate buffer
- B Hemoglobin buffer
- C Protein buffer
- D Bicarbonate buffer
Correct answer: Phosphate buffer
The phosphate buffer system binds hydrogen ions in the tubular fluid, allowing their excretion without excessive drop in urine pH.
Which nephron segment is most involved in bicarbonate reabsorption?
- A Distal tubule
- B Collecting duct
- C Loop of Henle
- D Proximal tubule
Correct answer: Proximal tubule
The proximal tubule reabsorbs approximately 80–90% of filtered bicarbonate. This is the major site for bicarbonate conservation.
In alkalosis, the kidney responds by:
- A Increasing hydrogen ion secretion
- B Increasing bicarbonate reabsorption
- C Increasing ammonium production
- D Decreasing bicarbonate reabsorption
Correct answer: Decreasing bicarbonate reabsorption
In alkalosis, the kidneys reduce bicarbonate reabsorption and increase its excretion to lower blood pH toward normal.
Which form of hydrogen ion excretion is most important during chronic acidosis?
- A Free hydrogen ions
- B Bicarbonate excretion
- C Carbon dioxide excretion
- D Ammonium excretion
Correct answer: Ammonium excretion
Ammonium excretion becomes the dominant mechanism during chronic acidosis, allowing large amounts of acid to be excreted safely.
Which transporter is responsible for sodium-hydrogen exchange in the proximal tubule?
- A Na+/H+ exchanger
- B Na+/K+ ATPase
- C Cl-/HCO3- exchanger
- D K+/H+ exchanger
Correct answer: Na+/H+ exchanger
The Na+/H+ exchanger facilitates hydrogen ion secretion into the tubular lumen in exchange for sodium reabsorption.
Which condition leads to decreased renal acid excretion?
- A Renal failure
- B Normal kidney function
- C Hyperventilation
- D Dehydration
Correct answer: Renal failure
Renal failure impairs hydrogen ion excretion and bicarbonate reabsorption, leading to metabolic acidosis.
Which type of intercalated cells secrete bicarbonate into the tubular lumen?
- A Type B cells
- B Type A cells
- C Principal cells
- D Juxtaglomerular cells
Correct answer: Type B cells
Type B intercalated cells secrete bicarbonate and reabsorb hydrogen ions, playing a role in correcting alkalosis.
Which substance combines with hydrogen ions to form ammonium in renal tubules?
- A Urea
- B Glucose
- C Creatinine
- D Ammonia
Correct answer: Ammonia
Ammonia combines with hydrogen ions to form ammonium, which is excreted in urine. This process helps eliminate acid.
Which renal process helps prevent excessive acidification of urine?
- A Glucose reabsorption
- B Phosphate buffering
- C Protein filtration
- D Sodium excretion
Correct answer: Phosphate buffering
Phosphate buffers hydrogen ions in the tubular fluid, preventing excessive lowering of urine pH.
Which condition is associated with increased bicarbonate reabsorption?
- A Metabolic acidosis
- B Metabolic alkalosis
- C Respiratory alkalosis
- D Hyperkalemia
Correct answer: Metabolic acidosis
In metabolic acidosis, the kidneys increase bicarbonate reabsorption to compensate for low blood pH.
Which ion is secreted in exchange for bicarbonate reabsorption in the proximal tubule?
- A Potassium
- B Sodium
- C Hydrogen
- D Calcium
Correct answer: Hydrogen
Hydrogen ions are secreted into the tubular lumen in exchange for bicarbonate reabsorption, maintaining acid-base balance.
Which renal adaptation occurs during chronic respiratory acidosis?
- A Decreased bicarbonate reabsorption
- B Increased bicarbonate reabsorption
- C Decreased hydrogen ion secretion
- D Reduced ammonium production
Correct answer: Increased bicarbonate reabsorption
In chronic respiratory acidosis, the kidneys increase bicarbonate reabsorption to compensate for elevated CO2 levels.
Which mechanism allows the kidney to excrete large amounts of acid without lowering urine pH excessively?
- A Excretion of free hydrogen ions in urine
- B Excretion of dissolved carbon dioxide
- C Buffering by phosphate and ammonia
- D Excretion of sodium into urine
Correct answer: Buffering by phosphate and ammonia
Buffering by phosphate and ammonia allows hydrogen ions to be excreted safely without excessively lowering urine pH.