BIOL 252 Human Anatomy & Physiology II
w/Lab Module 8 Exam: Fluid, Electrolyte, and
Acid-Base Balance |100 Questions with Correct
Answers and Expert Rationales
SECTION A: Fluid Compartments and Homeostasis (Questions
1-25)
1. The largest compartment of body water is the:
A) Plasma
B) Interstitial fluid
C) Intracellular fluid
D) Extracellular fluid
Correct Answer: C) Intracellular fluid
Expert Rationale: The intracellular fluid (ICF) compartment
contains approximately two-thirds of total body water. The
extracellular fluid (ECF), which includes plasma and interstitial
fluid, contains the remaining one-third .
2. The primary regulator of water intake is the:
A) Pituitary gland
B) Adrenal cortex
C) Hypothalamic thirst center
D) Medulla oblongata
,Correct Answer: C) Hypothalamic thirst center
Expert Rationale: The hypothalamic thirst center is the primary
regulator of water intake. When plasma osmolality increases or
blood pressure decreases, osmoreceptors and baroreceptors signal
the hypothalamus to stimulate thirst .
3. Which fluid compartment surrounds tissue cells and
provides a medium for nutrient and waste exchange?
A) Plasma
B) Interstitial fluid (ISF)
C) Intracellular fluid
D) Lymph
Correct Answer: B) Interstitial fluid
Expert Rationale: Interstitial fluid is the extracellular fluid that
bathes tissue cells and serves as the immediate environment for
nutrient and waste exchange between blood and cells. Plasma is the
fluid component of blood, while lymph is a specialized fluid
collected from interstitial spaces .
4. Osmosis is best defined as:
A) Movement of solutes across a membrane
B) Active transport of ions
C) Movement of water across a semipermeable membrane
D) Diffusion of gases
,Correct Answer: C) Movement of water across a
semipermeable membrane
Expert Rationale: Osmosis is the net movement of water molecules
across a semipermeable membrane from an area of higher water
concentration (lower solute concentration) to an area of lower
water concentration (higher solute concentration) .
5. Proper fluid balance is necessary to maintain optimal
cellular functioning by ensuring cells are adequately
hydrated, which supports enzymatic reactions, nutrient
uptake, and waste removal.
A) True
B) False
Correct Answer: A) True
Expert Rationale: Proper fluid balance is essential for cellular
function. Adequate hydration supports enzymatic reactions,
facilitates nutrient transport into cells, and enables efficient waste
removal from cells .
6. The amount of fluid in a compartment directly influences
electrolyte balance by:
A) Enhancing hormone secretion that degrades electrolytes
B) Completely preventing sodium reabsorption in the kidneys
C) Affecting the distribution and concentration of electrolytes
D) Suppressing kidney function
, Correct Answer: C) Affecting the distribution and
concentration of electrolytes
Expert Rationale: The amount of fluid in a compartment affects the
distribution and concentration of electrolytes. Changes in fluid
volume can dilute or concentrate electrolytes, influencing their
concentrations in body fluids .
7. Which clinical assessment measures how long it takes for
blood to re-perfuse tissue after pressure is applied?
A) Mucous membrane moisture
B) Respiratory rate
C) Capillary refill time
D) Skin turgor
Correct Answer: C) Capillary refill time
Expert Rationale: Capillary refill time is a clinical assessment that
measures how quickly blood returns to tissue after pressure is
applied. Normal capillary refill is under 2 seconds; prolonged refill
may indicate dehydration or poor perfusion .
8. A clinician performs a full hydration assessment. Skin
turgor shows an immediate response, mucous membranes
are moist, and capillary refill is under 2 seconds. This
indicates:
A) Normal hydration status
B) Overhydration
w/Lab Module 8 Exam: Fluid, Electrolyte, and
Acid-Base Balance |100 Questions with Correct
Answers and Expert Rationales
SECTION A: Fluid Compartments and Homeostasis (Questions
1-25)
1. The largest compartment of body water is the:
A) Plasma
B) Interstitial fluid
C) Intracellular fluid
D) Extracellular fluid
Correct Answer: C) Intracellular fluid
Expert Rationale: The intracellular fluid (ICF) compartment
contains approximately two-thirds of total body water. The
extracellular fluid (ECF), which includes plasma and interstitial
fluid, contains the remaining one-third .
2. The primary regulator of water intake is the:
A) Pituitary gland
B) Adrenal cortex
C) Hypothalamic thirst center
D) Medulla oblongata
,Correct Answer: C) Hypothalamic thirst center
Expert Rationale: The hypothalamic thirst center is the primary
regulator of water intake. When plasma osmolality increases or
blood pressure decreases, osmoreceptors and baroreceptors signal
the hypothalamus to stimulate thirst .
3. Which fluid compartment surrounds tissue cells and
provides a medium for nutrient and waste exchange?
A) Plasma
B) Interstitial fluid (ISF)
C) Intracellular fluid
D) Lymph
Correct Answer: B) Interstitial fluid
Expert Rationale: Interstitial fluid is the extracellular fluid that
bathes tissue cells and serves as the immediate environment for
nutrient and waste exchange between blood and cells. Plasma is the
fluid component of blood, while lymph is a specialized fluid
collected from interstitial spaces .
4. Osmosis is best defined as:
A) Movement of solutes across a membrane
B) Active transport of ions
C) Movement of water across a semipermeable membrane
D) Diffusion of gases
,Correct Answer: C) Movement of water across a
semipermeable membrane
Expert Rationale: Osmosis is the net movement of water molecules
across a semipermeable membrane from an area of higher water
concentration (lower solute concentration) to an area of lower
water concentration (higher solute concentration) .
5. Proper fluid balance is necessary to maintain optimal
cellular functioning by ensuring cells are adequately
hydrated, which supports enzymatic reactions, nutrient
uptake, and waste removal.
A) True
B) False
Correct Answer: A) True
Expert Rationale: Proper fluid balance is essential for cellular
function. Adequate hydration supports enzymatic reactions,
facilitates nutrient transport into cells, and enables efficient waste
removal from cells .
6. The amount of fluid in a compartment directly influences
electrolyte balance by:
A) Enhancing hormone secretion that degrades electrolytes
B) Completely preventing sodium reabsorption in the kidneys
C) Affecting the distribution and concentration of electrolytes
D) Suppressing kidney function
, Correct Answer: C) Affecting the distribution and
concentration of electrolytes
Expert Rationale: The amount of fluid in a compartment affects the
distribution and concentration of electrolytes. Changes in fluid
volume can dilute or concentrate electrolytes, influencing their
concentrations in body fluids .
7. Which clinical assessment measures how long it takes for
blood to re-perfuse tissue after pressure is applied?
A) Mucous membrane moisture
B) Respiratory rate
C) Capillary refill time
D) Skin turgor
Correct Answer: C) Capillary refill time
Expert Rationale: Capillary refill time is a clinical assessment that
measures how quickly blood returns to tissue after pressure is
applied. Normal capillary refill is under 2 seconds; prolonged refill
may indicate dehydration or poor perfusion .
8. A clinician performs a full hydration assessment. Skin
turgor shows an immediate response, mucous membranes
are moist, and capillary refill is under 2 seconds. This
indicates:
A) Normal hydration status
B) Overhydration
