Question

After a normal exhalation, some air is left in the "anatomic dead spaces" of the lungs and airways. This air cannot be used to oxygenate capillary blood, because it never comes in contact with the capillary network.  

Which of the following respiratory structures CANNOT be an "anatomic dead space"?

Group of answer choices

bronchus

bronchiole

trachea

alveolus

Answer 1

Option (d) Alveolus is correct answer.

Anatomical dead space :-
• The total volume of the conducting airways from the nose or mouth down to the level of the terminal bronchioles.
• It includes the trachea, bronchus, bronchioles, terminal bronchioles, and is about 150 ml on the average in humans.
• It contains the gas that is unchanged or has no role in gaseous exchange,
but the gas present in alveolus has role in gaseous exchange, it exchanges with capillary blood, so it it not a part of anatomical dead space.

Gas exchange :-
• It is the delivery of oxygen from the lungs to the bloodstream, and the elimination of carbon dioxide from the bloodstream to the lungs.
• It occurs in the lungs between the alveoli and a network of tiny blood vessels called capillaries, which are located in the walls of the alveoli.