What is the alveolar ventilation for person with vital capacity 500 mL, respiratory rate 14/min, tidal volume 500 mL and dead space 150 mL?
**Core Concept:**
The question asks to calculate alveolar ventilation, which is the measure of the amount of oxygen entering the lungs per minute and ultimately reaching the bloodstream. Alveolar ventilation can be calculated using the formula:
Alveolar ventilation = Respiratory rate × Tidal volume
**Why the Correct Answer is Right:**
In this case, the vital capacity (VC) is given as 500 mL, respiratory rate (RR) as 14/min, tidal volume (TV) as 500 mL, and dead space (DS) as 150 mL. To calculate alveolar ventilation (AV), we can use the formula:
Alveolar ventilation = Respiratory rate × Tidal volume
Substituting the given values:
Alveolar ventilation = 14/min × 500 mL
Alveolar ventilation = 7000 mL/min
**Why Each Wrong Option is Incorrect:**
A. Alveolar ventilation calculation involves respiratory rate and tidal volume, not vital capacity. Therefore, Option A is incorrect.
B. Similar to Option A, the formula involves respiratory rate and tidal volume, not vital capacity. This makes Option B incorrect as well.
C. Dead space is an important factor in determining alveolar ventilation, as it affects the total volume of air entering the lungs. However, the dead space in this case is correctly accounted for in the calculation. Therefore, Option C is incorrect.
D. Dead space is an important factor in determining alveolar ventilation, as it affects the total volume of air entering the lungs. However, the dead space in this case is correctly accounted for in the calculation. Therefore, Option D is incorrect.
**Clinical Pearl:**
Knowing the correct formula for alveolar ventilation and applying the given values accurately will help determine the correct answer. Alveolar ventilation is crucial in understanding oxygenation and carbon dioxide removal in the respiratory system.
**Correct Answer:**
Alveolar ventilation = Respiratory rate × Tidal volume
Alveolar ventilation = 14/min × 500 mL
Alveolar ventilation = 7000 mL/min
**Explanation:**
The correct answer shows how to calculate alveolar ventilation using respiratory rate (14 breaths/min) and tidal volume (500 mL). The result, 7000 mL/min, indicates the amount of oxygen entering the lungs per minute, which is essential for understanding the respiratory process and maintaining adequate oxygenation in the body.