Question 1

Which of the following equations correctly represents the relationship between plasma pH and hydrogen ion concentration?

Accepted Answer

$$pH = -\log[H^+]$$

Question 2

A patient presents with a plasma pH of 7.34. Which condition does this indicate?

Accepted Answer

Acidemia

Question 3

Which organ system is primarily responsible for excreting volatile acids produced by metabolism?

Accepted Answer

Respiratory system

Question 4

During acidosis, which compensatory mechanism is most likely to be activated first?

Accepted Answer

Respiratory increase in CO$$_2$$ excretion (hyperventilation)

Question 5

Which buffer system is most important in resisting changes in plasma pH in the extracellular fluid?

Accepted Answer

Bicarbonate buffer system

Question 6

If the body produces 20 moles of volatile acid per day, how is most of this acid eliminated?

Accepted Answer

Excreted by the lungs as CO$$_2$$

Question 7

Which amino acid metabolism produces a non-volatile acid that must be excreted by the kidneys?

Accepted Answer

Cysteine

Question 8

What is the primary urinary buffer system for acid excretion in the kidneys?

Accepted Answer

Phosphate buffer system

Question 9

Why is excretion of free H$$^+ in $$urine considered inefficient for acid elimination?

Accepted Answer

It would require an impractically large volume of urine

Question 10

Which of the following best describes the role of the ammonia buffer system in renal acid excretion?

Accepted Answer

It binds secreted H$$^+ in $$the tubular lumen to form NH$$_4^+$$ for excretion

Question 11

A patient is hyperventilating. What effect will this have on plasma pH?

Accepted Answer

Increase plasma pH (alkalemia)

Question 12

Which of the following is a consequence of abnormal plasma pH?

Accepted Answer

Impaired membrane transport

Question 13

Which equation represents the reaction catalyzed by carbonic anhydrase in the regulation of acid-base balance?

Accepted Answer

$$CO_2 + H_2O$$ \rightarrow H^+ + $$HCO_3$$^-$$

Question 14

Which of the following is NOT a buffer system used by the body to resist changes in pH?

Accepted Answer

Chloride buffer system

Question 15

Which renal process is responsible for conserving filtered bicarbonate?

Accepted Answer

Bicarbonate reabsorption in the proximal tubule

Question 16

A patient with chronic kidney disease is unable to excrete non-volatile acids efficiently. What is the most likely consequence?

Accepted Answer

Metabolic acidosis

Question 17

Which of the following best explains why the body uses buffer systems to regulate plasma pH?

Accepted Answer

Buffers resist changes in pH by reversibly binding H$$^+$$ ions

Question 18

Which of the following is a non-volatile acid produced by metabolism and excreted by the kidneys?

Accepted Answer

Sulfuric acid

Question 19

Which cell type in the kidney senses changes in acid-base status and adjusts H$$^+$$ secretion and bicarbonate reabsorption?

Accepted Answer

Renal tubular cells

Question 20

Which of the following is a correct sequence of events in the body's response to a non-volatile acid load?

Accepted Answer

Acid load enters plasma → buffered by bicarbonate → moves into cells → excreted by kidneys

Regulation of Acid-Base Balance: Mechanisms and Clinical Implications

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