Question 1

Which of the following best explains why infants have a higher percentage of body water compared to elderly adults?

Accepted Answer

Infants have lower bone mass and less body fat, resulting in a higher proportion of water.

Question 2

A patient is given an intravenous solution of 0.9% NaCl. Which fluid compartment will initially experience the greatest increase in volume?

Accepted Answer

Plasma (ECF)

Question 3

Which of the following statements about electrolyte composition is correct?

Accepted Answer

The major cation in the ECF is Na+, and the major cation in the ICF is K+.

Question 4

A person eats a very salty meal, increasing their ECF osmolality. What is the immediate effect on water movement?

Accepted Answer

Water moves from the ICF into the ECF.

Question 5

Which of the following is the primary stimulus for the release of antidiuretic hormone (ADH)?

Accepted Answer

A rise in plasma osmolality detected by hypothalamic osmoreceptors

Question 6

A marathon runner collapses after the race and is found to have confusion, muscle cramps, and cerebral edema. She drank only water during the race. What is the most likely diagnosis?

Accepted Answer

Hypotonic hydration (water intoxication)

Question 7

Which hormone is released in response to high blood pressure and acts to decrease blood volume and pressure by increasing sodium and water excretion?

Accepted Answer

Atrial natriuretic peptide (ANP)

Question 8

A patient with chronic renal failure develops hyperkalemia. Which of the following is a potential consequence?

Accepted Answer

Bradycardia and cardiac arrhythmias

Question 9

Which of the following best describes the effect of parathyroid hormone (PTH) on calcium homeostasis?

Accepted Answer

PTH increases calcium absorption in the small intestine by stimulating vitamin D activation.

Question 10

Which buffer system is the most important in the extracellular fluid (ECF)?

Accepted Answer

Bicarbonate buffer system

Question 11

A patient presents with the following arterial blood values: pH = 7.30, P$$_{CO_2$} = 50 mm Hg$$, HCO$$_3^- = 28 $$mEq/L. What is the most likely diagnosis?

Accepted Answer

Respiratory acidosis with renal compensation

Question 12

Which of the following equations represents the reversible reaction that is central to the bicarbonate buffer system?

Accepted Answer

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

Question 13

A patient with persistent vomiting is at risk for which acid-base disturbance?

Accepted Answer

Metabolic alkalosis

Question 14

Which of the following is a direct effect of aldosterone on the kidney tubules?

Accepted Answer

Increased reabsorption of sodium and secretion of potassium

Question 15

Which of the following best explains why edema does not cause cellular swelling?

Accepted Answer

Edema only increases the volume of the interstitial fluid, not the intracellular fluid.

Question 16

Which of the following is the most immediate and rapid mechanism for regulating blood pH?

Accepted Answer

Chemical buffer systems

Question 17

A patient with untreated diabetes mellitus develops ketoacidosis. Which acid-base imbalance is most likely?

Accepted Answer

Metabolic acidosis

Question 18

Which of the following would most likely result in hypernatremia?

Accepted Answer

Severe dehydration

Question 19

Which of the following is a consequence of blood pH falling below 6.8?

Accepted Answer

Depression of the central nervous system, leading to coma and death

Question 20

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

Accepted Answer

They regulate blood levels of alkaline substances and eliminate nonvolatile acids.

Fluid, Electrolyte, and Acid-Base Balance: Structured Study Notes

Study Guide - Practice Questions

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