Particles between what size range (in micrometers) are trapped in bronchi and bronchioles?

Particles in the size range of 2-10 micrometers are typically trapped in the bronchi and bronchioles due to the anatomical and physiological characteristics of the respiratory tract. When inhaled, air passes through the upper respiratory tract, where larger particles are filtered out by structures like the nose and the mucous membranes.

As air moves into the bronchi and subsequently into the bronchioles, the diameter decreases, creating a situation where particles in this specific size range (2-10 micrometers) cannot easily penetrate deeper into the alveoli. This is primarily due to inertial impaction, a mechanism where larger particles are unable to follow the curved pathways of the bronchi and are instead deposited onto the airway surfaces.

Particles smaller than 2 micrometers may bypass these air passages and reach the alveolar regions, while those larger than 10 micrometers are typically trapped in the larger airways. Therefore, the size range of 2-10 micrometers is critical in understanding how the respiratory system filters inhaled particles, making this the correct answer.