Question

The amount of blood in an average adult human is ________.

• A. 1 to 2 Liters
• B. 2 to 3 Liters
• C. 5 to 6 liters
• D. 6 to 8 liters

Hint:

When donating blood, a standard pint collected is about 450-500 mL. This represents less than 10% of your total blood volume (5-6 Liters), which is why healthy adults can donate without suffering adverse hemodynamic effects.

Answer 1

The Correct Option is C

Step 1: Concept:
The question asks for the standard physiological total blood volume of an average healthy human adult.

Step 2: Step-by-step Explanation:

• Blood constitutes roughly 7% to 8% of a person's total body weight.

• For an average adult male weighing approximately 70 kg (154 lbs), the total blood volume is calculated as roughly 70 kg \(\times\) 75 mL/kg, which equals about 5.25 liters.

• Generally, standard medical textbooks state that the average adult female has about 4.5 to 5.5 liters of blood, while the average adult male has about 5.0 to 6.0 liters of blood.

• Options A (1-2 L) and B (2-3 L) are vastly insufficient for maintaining adult hemodynamic stability, aligning closer to the blood volumes of infants or small children.

• Option D (6-8 L) is overly excessive and would typically only be seen in unusually large individuals or hypervolemic pathological states.

• Therefore, the universally accepted standard reference range for an average adult is 5 to 6 liters.

Step 3: Final Answer:
The correct volume is 5 to 6 liters.