High School

What is the ratio of dead space to tidal volume, or the fraction/percentage of tidal volume distributed to dead space, and how does it affect alveolar ventilation?

A) 1:1, it has no effect on alveolar ventilation
B) 1:2, it decreases alveolar ventilation
C) 2:1, it increases alveolar ventilation
D) 1:3, it significantly impairs alveolar ventilation

Answer :

Final answer:

The ratio of dead space to tidal volume is usually around 1:2, affecting alveolar ventilation by reducing the portion of inhaled air that reaches the alveoli for gas exchange.

Explanation:

The ratio of dead space to tidal volume, or the fraction/percentage of tidal volume distributed to dead space, is influenced by the anatomy of the respiratory system. Anatomical dead space refers to the air present in the airway that never reaches the alveoli for gas exchange, while alveolar dead space involves air within non-functioning alveoli. The total dead space is the sum of these two types of dead spaces.

The correct ratio of dead space to tidal volume can vary, but typically it is around 1:2. This means that for every 2 units of tidal volume, 1 unit is distributed to dead space. This dead space does not participate in gas exchange, which affects alveolar ventilation. With more dead space relative to tidal volume, there is a decrease in effective alveolar ventilation, because a larger portion of the inhaled air does not reach the alveoli where gas exchange occurs.

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