Anatomic Deadspace is the portion of air that does not participate in gas exchange.

Anatomic Deadspace is the portion of air that does not participate in gas exchange.

• A. Functional residual capacity
• B. Total lung capacity
• C. Anatomic Deadspace
• D. Vital capacity

Answer: (C)

Anatomic dead space is the portion of tidal air that fills the conducting airways (nose, pharynx, trachea, bronchi) where there are no alveoli, so no gas exchange occurs. In a healthy adult this is about 150 mL, meaning that air in these spaces does not participate in oxygening blood or removing CO2. The other terms describe lung volumes or capacities (the amount of air stored or moved during various breathing maneuvers) rather than the portion of air that avoids gas exchange. This is why the term that identifies the non-exchanging air is the correct one.

Anatomic dead space is the portion of tidal air that fills the conducting airways (nose, pharynx, trachea, bronchi) where there are no alveoli, so no gas exchange occurs. In a healthy adult this is about 150 mL, meaning that air in these spaces does not participate in oxygening blood or removing CO2. The other terms describe lung volumes or capacities (the amount of air stored or moved during various breathing maneuvers) rather than the portion of air that avoids gas exchange. This is why the term that identifies the non-exchanging air is the correct one.