,BIOL252/BIOL 252 Human Anatomy & Physiology II w/Lab
Module 8 Exam | Portage Learning | 2026 Edition (PDF)
1. What are the two major fluid compartments of the body?
A) Plasma and Interstitial
B) Blood and Lymph
C) Intravascular and Transcellular
D) Intracellular and Extracellular
Correct Answer: Intracellular and Extracellular
Rationale: The two major fluid compartments are the intracellular fluid (ICF) and extracellular fluid (ECF).
The ICF is the fluid within cells, while the ECF is outside cells and includes plasma, interstitial fluid, and
transcellular fluid.
2. Approximately what percentage of total body weight is water in an average adult male?
A) 40%
B) 50%
C) 60%
D) 75%
Correct Answer: 60%
Rationale: Total body water accounts for approximately 60% of body weight in an average adult male.
Females have slightly less due to higher body fat content.
3. Which fluid compartment contains approximately 2/3 of the body's total water?
A) Plasma
B) Interstitial fluid
C) Intracellular fluid
,D) Transcellular fluid
Correct Answer: Intracellular fluid
Rationale: The intracellular fluid compartment contains approximately 2/3 of total body water. The
extracellular fluid contains the remaining 1/3.
4. Which of the following correctly describes the electrolyte composition of intracellular fluid?
A) High sodium, low potassium
B) High potassium, low sodium
C) Equal sodium and potassium
D) High chloride, low phosphate
Correct Answer: High potassium, low sodium
Rationale: Intracellular fluid has high concentrations of potassium (K⁺), magnesium (Mg²⁺), phosphate,
and proteins, but low concentrations of sodium and chloride.
5. Which of the following is the main cation in the extracellular fluid and is essential for maintaining
blood volume and blood pressure?
A) Potassium
B) Calcium
C) Sodium
D) Magnesium
Correct Answer: Sodium
Rationale: Sodium is the main cation in extracellular fluid. It plays a crucial role in maintaining blood
volume, blood pressure, and fluid balance, as well as nerve impulse transmission and muscle
contraction.
, 6. The thirst mechanism is the primary regulator of which of the following?
A) Sodium excretion
B) Potassium levels
C) Water intake
D) Acid-base balance
Correct Answer: Water intake
Rationale: The thirst mechanism is the primary regulator of water intake. When plasma osmolality
increases or blood volume decreases, the thirst center in the hypothalamus is stimulated, prompting the
individual to drink water.
7. Which hormone is the primary regulator of water excretion by the kidneys?
A) Aldosterone
B) Atrial natriuretic peptide (ANP)
C) Antidiuretic hormone (ADH)
D) Renin
Correct Answer: Antidiuretic hormone (ADH)
Rationale: Antidiuretic hormone (ADH), released from the posterior pituitary, is the primary hormone
regulating water excretion. ADH increases water reabsorption in the collecting ducts of the kidneys,
concentrating urine and conserving water.
8. A patient has a plasma osmolality of 295 mOsm/kg. Which hormone is most likely to be elevated?
A) Aldosterone
B) Atrial natriuretic peptide (ANP)
C) Antidiuretic hormone (ADH)
D) Renin
Module 8 Exam | Portage Learning | 2026 Edition (PDF)
1. What are the two major fluid compartments of the body?
A) Plasma and Interstitial
B) Blood and Lymph
C) Intravascular and Transcellular
D) Intracellular and Extracellular
Correct Answer: Intracellular and Extracellular
Rationale: The two major fluid compartments are the intracellular fluid (ICF) and extracellular fluid (ECF).
The ICF is the fluid within cells, while the ECF is outside cells and includes plasma, interstitial fluid, and
transcellular fluid.
2. Approximately what percentage of total body weight is water in an average adult male?
A) 40%
B) 50%
C) 60%
D) 75%
Correct Answer: 60%
Rationale: Total body water accounts for approximately 60% of body weight in an average adult male.
Females have slightly less due to higher body fat content.
3. Which fluid compartment contains approximately 2/3 of the body's total water?
A) Plasma
B) Interstitial fluid
C) Intracellular fluid
,D) Transcellular fluid
Correct Answer: Intracellular fluid
Rationale: The intracellular fluid compartment contains approximately 2/3 of total body water. The
extracellular fluid contains the remaining 1/3.
4. Which of the following correctly describes the electrolyte composition of intracellular fluid?
A) High sodium, low potassium
B) High potassium, low sodium
C) Equal sodium and potassium
D) High chloride, low phosphate
Correct Answer: High potassium, low sodium
Rationale: Intracellular fluid has high concentrations of potassium (K⁺), magnesium (Mg²⁺), phosphate,
and proteins, but low concentrations of sodium and chloride.
5. Which of the following is the main cation in the extracellular fluid and is essential for maintaining
blood volume and blood pressure?
A) Potassium
B) Calcium
C) Sodium
D) Magnesium
Correct Answer: Sodium
Rationale: Sodium is the main cation in extracellular fluid. It plays a crucial role in maintaining blood
volume, blood pressure, and fluid balance, as well as nerve impulse transmission and muscle
contraction.
, 6. The thirst mechanism is the primary regulator of which of the following?
A) Sodium excretion
B) Potassium levels
C) Water intake
D) Acid-base balance
Correct Answer: Water intake
Rationale: The thirst mechanism is the primary regulator of water intake. When plasma osmolality
increases or blood volume decreases, the thirst center in the hypothalamus is stimulated, prompting the
individual to drink water.
7. Which hormone is the primary regulator of water excretion by the kidneys?
A) Aldosterone
B) Atrial natriuretic peptide (ANP)
C) Antidiuretic hormone (ADH)
D) Renin
Correct Answer: Antidiuretic hormone (ADH)
Rationale: Antidiuretic hormone (ADH), released from the posterior pituitary, is the primary hormone
regulating water excretion. ADH increases water reabsorption in the collecting ducts of the kidneys,
concentrating urine and conserving water.
8. A patient has a plasma osmolality of 295 mOsm/kg. Which hormone is most likely to be elevated?
A) Aldosterone
B) Atrial natriuretic peptide (ANP)
C) Antidiuretic hormone (ADH)
D) Renin
