NEET BIOLOGY

Detailed explanation-1: -The bronchioles are the final air conductors, and by definition, lack cartilage altogether (and are therefore sometimes referred to as membranous) (Fig. 1.11). The bronchioles have no alveoli; alveoli are acquired more distally in the pulmonary acinus.

Detailed explanation-2: -Bronchioles lack supporting cartilage skeletons and have a diameter of around 1 mm. They are initially ciliated and graduate to the simple columnar epithelium and their lining cells no longer contain mucous producing cells.

Detailed explanation-3: -Terminal Bronchioles. This is the last part of the conducting portion of the respiratory system, and has the smallest diameter of all (less than 1mm). There is no cartilage, or glands, some smooth muscle is still present, there are no goblet cells.

Detailed explanation-4: -The tertiary bronchi eventually branch into bronchioles, airways less than a millimeter in diameter, which lack cartilage and glands but still have smooth muscle.

Detailed explanation-5: -Bronchi and Bronchial Tree The cartilage and mucous membrane of the primary bronchi are similar to that in the trachea. As the branching continues through the bronchial tree, the amount of hyaline cartilage in the walls decreases until it is absent in the smallest bronchioles.