Question 1

Which of the following best describes the effect of antidiuretic hormone (ADH) on the kidneys?

Accepted Answer

ADH increases the insertion of aquaporins in the distal tubule and collecting ducts, leading to increased water reabsorption.

Question 2

A patient is admitted with severe dehydration after running a marathon in hot weather without fluid replacement. Which of the following changes would you expect in their extracellular fluid (ECF)?

Accepted Answer

Increased ECF osmolarity and decreased ECF volume

Question 3

Which of the following equations correctly 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 4

A patient with chronic obstructive pulmonary disease (COPD) is hypoventilating. Which acid-base imbalance are they most at risk for, and what would you expect their arterial blood gas (ABG) results to show?

Accepted Answer

Respiratory acidosis; decreased pH and increased $$\mathrm{P_{CO_2$}}$$

Question 5

Which hormone is primarily responsible for increasing sodium ion reabsorption in the kidneys, and what is its effect on potassium?

Accepted Answer

Aldosterone; increases sodium reabsorption and stimulates potassium secretion

Question 6

A patient presents with muscle weakness and cardiac arrhythmias after taking a diuretic. Laboratory tests reveal hypokalemia. Which of the following best explains the effect of hypokalemia on excitable cells?

Accepted Answer

It hyperpolarizes the resting membrane potential, making cells less responsive to stimuli.

Question 7

Which of the following scenarios would most likely result in hyponatremia?

Accepted Answer

Drinking an excessive amount of water in a short period of time

Question 8

A patient with chronic kidney disease is unable to excrete sufficient hydrogen ions. What acid-base imbalance are they at risk for, and what is the primary compensatory mechanism?

Accepted Answer

Metabolic acidosis; hyperventilation to decrease $$\mathrm{CO_2$}$$

Question 9

Which of the following best describes the movement of water between the plasma and interstitial fluid at the arteriolar and venular ends of a capillary?

Accepted Answer

Hydrostatic pressure pushes water out at the arteriolar end; osmotic pressure pulls water in at the venular end.

Question 10

Which of the following buffer systems is most important for resisting changes in blood pH?

Accepted Answer

Carbonic acid-bicarbonate buffer system

Question 11

A patient is experiencing prolonged vomiting. Which acid-base imbalance are they most likely to develop, and what is the expected compensatory respiratory response?

Accepted Answer

Metabolic alkalosis; hypoventilation to retain $$\mathrm{CO_2$}$$

Question 12

Which of the following best explains why hypercalcemia can lead to nervous system depression?

Accepted Answer

Excess calcium decreases neuronal sodium permeability, reducing the ability to depolarize.

Question 13

Which of the following is a direct effect of angiotensin-II during dehydration?

Accepted Answer

It stimulates thirst, vasoconstriction, and the release of aldosterone and ADH.

Question 14

Which of the following best describes the effect of a hypertonic extracellular fluid (ECF) on a cell?

Accepted Answer

Water moves out of the cell, causing it to shrink.

Question 15

Which of the following is a function of the phosphate buffer system?

Accepted Answer

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

Question 16

A patient with severe diarrhea is losing large amounts of bicarbonate ions. What acid-base imbalance are they at risk for, and what is the primary compensatory mechanism?

Accepted Answer

Metabolic acidosis; increased respiratory rate to eliminate $$\mathrm{CO_2$}$$

Question 17

Which of the following best describes the principle of mass balance as it applies to fluid and electrolyte homeostasis?

Accepted Answer

The amount gained by the body must equal the amount lost.

Question 18

Which of the following is a direct effect of parathyroid hormone (PTH) when extracellular calcium levels drop?

Accepted Answer

It stimulates osteoclasts to release calcium from bone.

Question 19

Which of the following best explains why hyperkalemia is potentially fatal?

Accepted Answer

It makes the resting membrane potential of excitable cells more positive, impairing their function.

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

Study Guide - Practice Questions

Study Guide - Flashcards