Posted: July 25th, 2017

Scanning of inhaled, radioactively labeled aerosols has been used to study the distribution of pulmonary ventilation. However, data obtained using aerosols with a particle diameter of 20 μ do not accurately reflect the distribution of alveolar ventilation in the lungs. Which of the following is the best explanation for this finding?

Scanning of inhaled, radioactively labeled
aerosols has been used to study the distribution
of pulmonary ventilation. However, data
obtained using aerosols with a particle diameter
of 20 μ do not accurately reflect the distribution
of alveolar ventilation in the lungs. Which of the
following is the best explanation for this finding?
(A) Ingestion of these particles by alveolar
macrophages occurs nonuniformly
(B) The majority of particles this size do not
adhere to airway or alveolar walls
(C) Many particles are rapidly absorbed into
the pulmonary capillary blood
(D) Most particles this size are deposited in
the conducting airways
(E) Removal of particles by the mucociliary
system is too fast to allow scanning