Question 1

Three individuals,each weighing 55 kg and each having a plasma [Na⁺] of 145 mEq/L,receive infusions of different solutions.Individual A receives 1 L of isotonic NaCl (290 mOsm/kg H₂O); individual B receives 1 L of a mannitol solution (290 mOsm/kg H₂O); and individual C receives 1 L of a 5% dextrose in water (D₅W)solution (290 mOsm/kg H₂O).Assuming that there is no urine output,and after complete equilibration of the extracellular and intracellular fluid,which of these individuals will have a lower plasma [Na⁺]?

A)Individual A (NaCl infusion).
B)Individual B (mannitol infusion).
C)Individual C (D₅W infusion).
D)Individuals A,B,and C will have the same plasma [Na⁺].

Accepted Answer

B

Question 2

Intravenous infusion of 2 L of which of the following solutions will lead to the largest increase in intracellular fluid volume? A)D₅W B)Isotonic NaCl C)Hypotonic NaCl D)Hypertonic NaCl

Accepted Answer

D₅W (5% dextrose in water) is initially isotonic but becomes hypotonic as the dextrose is metabolized, leading to a net increase in intracellular fluid volume as water moves into cells.

Question 3

Intracellular fluid volume is normally what percentage of body weight?&#10;A)60%&#10;B)40%&#10;C)20%&#10;D)10%&#10;E)5%

Accepted Answer

Intracellular fluid (ICF) volume is normally about 40% of body weight. This is because the body is made up of approximately 60% water, with two-thirds of that water being intracellular.

Question 4

A 100 mmol/L solution of MgCl₂ would be expected to have an osmolality of which of the following? A)50 mOsm/kg H₂O B)100 mOsm/kg H₂O C)200 mOsm/kg H₂O D)300 mOsm/kg H₂O E)350 mOsm/kg H₂O

Accepted Answer

MgCl2 dissociates into three ions (Mg2+ and 2 Cl-), so a 100 mmol/L solution results in 300 mmol/L of particles, equating to an osmolality of 300 mOsm/kg H2O.

Deck 2: Homeostasis of Body Fluids