$$\text{Osmolarity (osmol/L)} = \text{Molarity (mol/L)} \times \text{number of particles per molecule in solution}$$

Question 1

Which of the following best describes the distribution of body water in a healthy young adult male?

Accepted Answer

About 60% of body weight is water, with two-thirds of this water found in the intracellular fluid compartment.

Question 2

Which of the following is NOT a function of body water?

Accepted Answer

Serves as a primary energy source for metabolism

Question 3

A patient is given an intravenous solution with an osmolarity of 2 OsM NaCl. Compared to plasma, this solution is:

Accepted Answer

Hyperosmotic

Question 4

Which equation correctly relates osmolarity to molarity for a solution?

Accepted Answer

$$	ext{Osmolarity (osmol/L)} = 	ext{Molarity (mol/L)} 	imes 	ext{number of particles per molecule in solution}$$

Question 5

If a red blood cell is placed in a hypotonic solution, what will happen to the cell?

Accepted Answer

It will swell and possibly burst due to water gain.

Question 6

Which hormone is released in response to increased plasma osmolarity and acts to conserve body water?

Accepted Answer

Antidiuretic hormone (ADH)

Question 7

A patient with Addison's disease is most likely to experience which type of fluid imbalance?

Accepted Answer

Volume depletion (hypovolemia)

Question 8

Which of the following best defines osmosis?

Accepted Answer

Movement of water from an area of low solute concentration to high solute concentration across a selectively permeable membrane

Question 9

Calculate the osmolarity of a 1 mol/L NaCl solution, assuming complete dissociation.

Accepted Answer

$$2 	ext{ OsM}$$

Question 10

Which of the following scenarios would most likely result in hypotonic hydration (water intoxication)?

Accepted Answer

Drinking large amounts of plain water after losing both water and salt through sweating

Question 11

Which compartment contains the largest proportion of total body water?

Accepted Answer

Intracellular fluid

Question 12

Which of the following is a consequence of increased osmolarity in the extracellular fluid (ECF)?

Accepted Answer

Water moves out of cells, causing them to shrink.

Question 13

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

Accepted Answer

Increases water reabsorption

Question 14

A solution that causes no net change in cell volume when a cell is placed in it is described as:

Accepted Answer

Isotonic

Question 15

Which of the following is the minimum obligatory urine output required to excrete metabolic wastes in a healthy adult?

Accepted Answer

400 mL/day

Question 16

Which of the following best explains why edema can occur during fluid sequestration?

Accepted Answer

Excess fluid accumulates in a particular location, reducing circulating blood volume

Question 17

Which of the following is the correct formula for calculating osmotic pressure ($$\pi) $$using van't Hoff's law?

Accepted Answer

$$\pi = iMRT$$

Question 18

Which of the following is a major source of metabolic water in the body?

Accepted Answer

Oxidation of nutrients during cellular respiration

Question 19

A patient with chronic vomiting and diarrhea is most likely to develop which type of fluid imbalance?

Accepted Answer

Volume depletion (hypovolemia)

Question 20

Which of the following best describes the role of osmoreceptors in the hypothalamus?

Accepted Answer

They monitor the osmolarity of the extracellular fluid and stimulate thirst when osmolarity increases.

Body Water: Distribution, Functions, and Fluid Balance

Study Guide - Practice Questions