Topics:
Animal Physiology, Animal Refresher
Normal Dead Space Volume of Lungs
Normal dead space volume of lungs in human being is:
- 125 ml
- 150 ml — Correct Answer
- 175 ml
- 200 ml
Explanation:
Correct Answer: 150 ml
The anatomical dead space (volume of air that fills the conducting airways but does NOT participate in gas exchange) is approximately 150 ml in humans.
Types of Dead Space
- Anatomical dead space: Volume in conducting airways (trachea, bronchi, bronchioles) = ~150 ml. No gas exchange occurs here.
- Alveolar dead space: Volume in alveoli that are ventilated but not perfused = near zero in healthy individuals.
- Physiological dead space: Anatomical + Alveolar dead space = total volume not participating in gas exchange.
Clinical Significance
- In disease (e.g., pulmonary embolism), alveolar dead space increases → impaired gas exchange.
- Of the 500 ml tidal volume, only 500 − 150 = 350 ml reaches the alveoli for gas exchange.
- Normal GFR: 125 ml/min (not to be confused with dead space of 150 ml).
📚 About this Topic — Animal Physiology
This multiple choice question is from Animal Physiology, Animal Refresher. It has 4 options with a detailed explanation of the correct answer. Practice more MCQs from Animal Physiology to strengthen your preparation.
