RENAL PHYSIOLOGY: PRACTICE QUESTIONS
Acid-Base Balance

1. In which of the following fluids is the pH highest (most alkaline)? (Assume the person is normal.)

A. systemic arterial blood plasma
B. systemic venous blood plasma
C. urine
D. all of the above, since pH is normally of the same for all
E. A and B above, since blood plasma pH is relatively uniform

2. The ammonium (NH4+) ion that may be present in urine is produced by

A. breakdown of urea in the liver
B. metabolism of amino acid in the renal tubule and collecting duct
C. aerobic carbohydrate metabolism
D. gylcolytic pathways during anaerobic metabolism
E. gluconeogensis during starvation

3. The reason that respiratory compensation for metabolic alkalosis can never be complete (return plasma pH to normal) is that (Note: PaCO2 = systemic arterial carbon dioxide partial pressure.)

A. high PaCO2 inhibits respiratory ventilation
B. high PaCO2 stimulates respiratory ventilation
C. low PaCO2 inhibits respiratory ventilation
D. low PaCO2 stimulates respiratory ventilation
E. none of the above, since respiratory compensation for metabolic alkalosis can be complete

4. The appearance of large amounts of ammonium ion (NH4+) in the urine is characteristic of the renal response to

A. respiratory acidosis
B. respiratory alkalosis
C. acidosis resulting from pancreatic diabetes
D. alkalosis resulting from gastric vomiting
E. both A and C above

5. An individual hoping for an LSD "acid high" mistakenly gives himself an intravenous injection of hydrochloric acid. The responses of his body which attempt to compensate for this ignorance of physiology include all of the following except

A. hyperventilation
B. increase in the acid form of the blood fixed buffers
C. decrease in blood bicarbonate ion concentration
D. increase in urine bicarbonate ion excretion
E. increase in urine ammonium ion excretion

6. A systemic arterial blood sample taken from the above individual an hour after his HCl "adventure" might show which of the following?

A. HCO3- = 34 meq/liter; PaCO2 = 50 mmHg
B. HCO3- = 34 meq/liter; PaCO2 = 30 mmHg
C. HCO3- = 14 meq/liter; PaCO2 = 50 mmHg
D. HCO3- = 14 meq/liter; PaCO2 = 30 mmHg
E. HCO3- = 24 meq/liter; PaCO2 = 40 mmHg

7. A young woman is found comatose, having taken an unknown number of sleeping pills an unknown time before. An arterial blood sample yields the following values:

pH      6.90
HCO3-   13 meq/liter
PaCO2   68 mmHg

This patient's acid-base status is most accurately described as

A. uncompensated metabolic acidosis
B. uncompensated respiratory acidosis
C. simultaneous respiratory and metabolic acidosis
D. respiratory acidosis with partial renal compensation
E. respiratory acidosis with complete renal compensation