Question 1

A 70-year-old man is admitted to the hospital with severe dehydration after several days of vomiting and diarrhea. Which of the following best explains the physiological changes in his body fluid compartments?

Accepted Answer

Water moves from the ICF to the ECF, causing cellular shrinkage.

Question 2

Which of the following is the primary mechanism by which antidiuretic hormone (ADH) reduces water loss in the body?

Accepted Answer

Stimulating water reabsorption in the collecting ducts of the kidneys

Question 3

A patient presents with muscle cramps, confusion, and brain edema after drinking several liters of water in a short period. Laboratory tests reveal low plasma sodium. What is the most likely diagnosis?

Accepted Answer

Hypotonic hydration

Question 4

Which hormone acts to decrease blood pressure by inhibiting sodium and water reabsorption in the kidneys, suppressing ADH, renin, and aldosterone release, and causing vasodilation?

Accepted Answer

Atrial natriuretic peptide (ANP)

Question 5

Which of the following best describes the effect of aldosterone on electrolyte balance?

Accepted Answer

It increases sodium reabsorption and potassium secretion.

Question 6

A patient with chronic obstructive pulmonary disease (COPD) has an arterial blood pH of 7.30 and a $$pCO_2 of 50 mm Hg. $$Which acid-base disorder is present?

Accepted Answer

Respiratory acidosis

Question 7

Which buffer system is the most important for maintaining acid-base balance in the extracellular fluid (ECF)?

Accepted Answer

Bicarbonate buffer system

Question 8

If a person ingests a large amount of sodium bicarbonate ($$NaHCO_3$$), which acid-base disturbance is most likely to occur?

Accepted Answer

Metabolic alkalosis

Question 9

Which of the following equations correctly represents the bicarbonate buffer system's response to a strong acid in the blood?

Accepted Answer

$$ HCl + NaHCO_3 \rightarrow H_2CO_3 + NaCl $$

Question 10

A patient with uncontrolled diabetes mellitus develops rapid, deep breathing (Kussmaul respirations). Which of the following best explains this compensatory response?

Accepted Answer

The patient is compensating for metabolic acidosis by increasing CO$$_2$$ exhalation.

Question 11

Which of the following best describes the effect of increased plasma osmolarity on the thirst mechanism?

Accepted Answer

It stimulates the hypothalamic thirst center, increasing water intake.

Question 12

Which of the following is the primary cation in the intracellular fluid (ICF)?

Accepted Answer

Potassium ($$K^+)$$

Question 13

A patient is found to have a blood pH of 7.50 and a low $$pCO_2. $$Which of the following is the most likely acid-base disturbance?

Accepted Answer

Respiratory alkalosis

Question 14

Which of the following best explains why edema can occur in patients with liver failure?

Accepted Answer

Decreased plasma protein synthesis reduces colloid osmotic pressure, allowing fluid to accumulate in the interstitial space.

Question 15

Which of the following best describes the renal compensation for respiratory acidosis?

Accepted Answer

The kidneys retain bicarbonate ($$HCO_3$$^-$$) and excrete more hydrogen ions (H$$^+$$).

Question 16

Which of the following is a direct effect of parathyroid hormone (PTH) on calcium and phosphate balance?

Accepted Answer

PTH increases calcium release from bone and inhibits phosphate reabsorption in the kidneys.

Question 17

Which of the following best describes the relationship between hydrogen ion concentration and potassium secretion in the renal tubules?

Accepted Answer

As $$[H^+]$$ increases (acidosis), potassium secretion decreases.

Question 18

Which of the following equations represents the phosphate buffer system's response to a strong base in the urine?

Accepted Answer

$$ NaOH + NaH_2PO_4 \rightarrow Na_2HPO_4 + H_2O $$

Question 19

A patient with severe vomiting is found to have a blood pH of 7.48 and elevated bicarbonate ($$HCO_3$$^-$$) levels. Which acid-base disorder is most likely present?

Accepted Answer

Metabolic alkalosis

Question 20

Which of the following best explains why sodium ($$Na^+) is $$the most important ion in determining extracellular fluid (ECF) volume?

Accepted Answer

Sodium is actively transported and water follows sodium, so changes in $$[Na^+]$$ directly affect ECF volume.

Chapter 26 Fluid, Electrolyte, and Acid-Base Balance: ANP Study Notes

Study Guide - Practice Questions

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