Question 1

Which of the following best explains why maintaining arterial pH between 7.35 and 7.45 is critical for normal cellular function?

Accepted Answer

Because proteins rely on a specific three-dimensional shape that can be altered by changes in pH, affecting their function.

Question 2

A patient presents with a blood pH of 7.28, rapid breathing, and a history of kidney failure. Which acid-base disturbance is most likely, and what is the primary compensatory mechanism?

Accepted Answer

Metabolic acidosis; compensation by increased respiratory rate to lower $$PCO_2$$

Question 3

Which equation correctly represents the carbonic acid-bicarbonate buffer system in the body?

Accepted Answer

$$CO_2 + H_2O$$ \Leftrightarrow H_2CO_3 \Leftrightarrow H^+ + $$HCO_3$$^-$$

Question 4

During intense exercise, which of the following best describes how the respiratory system helps maintain acid-base balance?

Accepted Answer

Increased respiration eliminates excess $$CO_2$$, reducing $$H_2CO_3$$ formation and preventing acidosis.

Question 5

Which buffer system is most important in the cytosol and kidney tubules, and what are its main components?

Accepted Answer

Phosphate buffer system; dihydrogen phosphate ($$H_2PO_4^-) $$and monohydrogen phosphate ($$HPO_4$$^{2-}$$)

Question 6

A patient with emphysema is likely to develop which acid-base disturbance, and what is the expected change in arterial $$PCO_2$$?

Accepted Answer

Respiratory acidosis; increased arterial $$PCO_2$$

Question 7

Which of the following best describes the role of hemoglobin in acid-base balance within systemic capillary beds?

Accepted Answer

Hemoglobin binds $$H^+$$ ions generated from $$CO_2$$ transport, helping buffer changes in pH.

Question 8

Which of the following scenarios is most likely to result in metabolic alkalosis?

Accepted Answer

Prolonged vomiting leading to loss of gastric acid

Question 9

If a patient ingests a large amount of sodium bicarbonate, which buffer system is primarily involved in neutralizing the excess base?

Accepted Answer

Carbonic acid-bicarbonate buffer system

Question 10

Which of the following best explains why the carbonic acid-bicarbonate buffer system is not effective at buffering changes in $$PCO_2$$?

Accepted Answer

Because both $$CO_2$$ and $$H_2CO_3$$ are part of the same equilibrium, so changes in $$PCO_2$$ directly affect both sides of the buffer equation.

Question 11

A climber rapidly ascends to high altitude and develops tingling and muscle spasms. Blood gas analysis shows increased pH, decreased $$PCO_2$$, and decreased $$HCO_3$$^-$$. What is the most likely diagnosis?

Accepted Answer

Respiratory alkalosis

Question 12

Which of the following best describes the compensation for metabolic acidosis?

Accepted Answer

Increased respiratory rate to decrease $$PCO_2$$

Question 13

Which chemical buffer system is most abundant in blood plasma and cytosol?

Accepted Answer

Protein buffer system

Question 14

A patient with prolonged diarrhea is at risk for which acid-base disturbance, and what is the primary mechanism?

Accepted Answer

Metabolic acidosis; loss of $$HCO_3$$^-$$ from the body

Question 15

Which of the following equations represents the phosphate buffer system in the kidney tubules?

Accepted Answer

$$H_2PO_4^- \Leftrightarrow H^+ + $$HPO_4$$^{2-}$$

Question 16

Which of the following is a direct effect of acidosis (blood pH \u003c 7.35) on the nervous system?

Accepted Answer

Depresses synaptic transmission, leading to disorientation and possible coma.

Question 17

Which of the following best describes the role of the kidneys in acid-base balance?

Accepted Answer

They excrete fixed acids and can generate or secrete $$HCO_3$$^-$$ as needed.

Question 18

A patient is found to have increased arterial $$PCO_2$$, decreased pH, and increased $$HCO_3$$^-$$. Which acid-base disturbance and compensation are present?

Accepted Answer

Respiratory acidosis with renal compensation (increased $$HCO_3$$^-$$ reabsorption)

Question 19

Which of the following best explains why high-protein diets can lead to a tendency toward acidosis?

Accepted Answer

High-protein diets produce more acids than bases during metabolism.

Acid-Base Balance and Buffer Systems in Human Physiology

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