Question 1

Which of the following best describes the main difference in solute composition between plasma and interstitial fluid?

Accepted Answer

Plasma contains a much higher protein content than interstitial fluid.

Question 2

A patient is admitted with severe dehydration. Which of the following best describes the movement of water between the extracellular fluid (ECF) and the cytosol (ICF) in this scenario?

Accepted Answer

Water moves from the cytosol to the ECF, causing cells to shrink.

Question 3

Which hormone plays the most important role in balancing water intake with water loss, and what is its primary action?

Accepted Answer

ADH (antidiuretic hormone); triggers insertion of aquaporins in kidney tubules to increase water reabsorption.

Question 4

A patient presents with muscle weakness and cardiac arrhythmias. Laboratory results show a plasma potassium concentration of 2.8 mEq/l. Which condition does this patient most likely have, and what is a common cause?

Accepted Answer

Hypokalemia; commonly caused by diuretic overuse.

Question 5

Which of the following equations represents the carbonic acid–bicarbonate buffer system in the blood?

Accepted Answer

$$ \mathrm{CO_2 + H_2O \leftrightarrow H_2CO_3 \leftrightarrow HCO_3^- + H^+} $$

Question 6

A patient with chronic kidney disease is unable to excrete fixed acids efficiently. What acid-base imbalance is this patient at risk for, and what is the expected compensatory response?

Accepted Answer

Metabolic acidosis; respiratory compensation by hyperventilation to decrease CO2.

Question 7

Which of the following best explains why overhydration can lead to hyponatremia?

Accepted Answer

The number of sodium ions remains the same, but the amount of water increases, diluting the sodium concentration.

Question 8

Which of the following is a function of water in the body?

Accepted Answer

Acts as a polar solvent, distributes heat, cushions and lubricates organs and tissues.

Question 9

A patient is given an intravenous solution that is hypertonic relative to their cytosol. What is the most likely effect on their cells?

Accepted Answer

Cells will lose water and shrink.

Question 10

Which of the following best describes the role of the phosphate buffer system?

Accepted Answer

It buffers changes in pH in the cytosol and kidney tubules.

Question 11

Which of the following is a consequence of severe hypocalcemia?

Accepted Answer

Spontaneous firing of neurons leading to tetanic muscle contractions.

Question 12

A patient with a blood pH of 7.28, low HCO3–, and rapid, deep breathing is most likely experiencing which condition?

Accepted Answer

Metabolic acidosis with respiratory compensation.

Question 13

Which of the following best describes obligatory water loss?

Accepted Answer

The minimum amount of urine (about 500 ml) produced daily to prevent toxic buildup.

Question 14

Which of the following ions is found in much higher concentration in the cytosol compared to the extracellular fluid?

Accepted Answer

Potassium (K+)

Question 15

A patient with a plasma sodium concentration of 150 mEq/l is most likely experiencing which condition, and what is a common cause?

Accepted Answer

Hypernatremia; commonly caused by dehydration.

Question 16

Which of the following best explains why the body must maintain a blood pH between 7.35 and 7.45?

Accepted Answer

To prevent cellular damage and maintain proper enzyme function.

Question 17

Which of the following is a real-life scenario that could lead to metabolic alkalosis?

Accepted Answer

Prolonged vomiting resulting in loss of gastric acid.

Question 18

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

Accepted Answer

It increases sodium reabsorption and potassium secretion in the kidneys.

Question 19

A patient with edema has fluid accumulation in the interstitial space. Which of the following best describes the tonicity of this accumulated fluid compared to the cytosol?

Accepted Answer

The accumulated fluid is isotonic to the cytosol.

Question 20

Which of the following best describes the role of osmoreceptors in the regulation of thirst?

Accepted Answer

They detect changes in plasma osmolarity and stimulate the thirst center in the hypothalamus.

Fluid, Electrolyte, and Acid-Base Homeostasis: Study Notes

Study Guide - Practice Questions

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