QS Study

Bronchial tree

Successive stages of division of trachea up to alveoli from the bronchial tree. It is the branching system of bronchi and bronchioles, conducting air from the windpipe into the lungs. It is the trachea branches into the right and left primary bronchi at the carina. The bronchi branch into smaller and smaller passageways until they terminate in tiny air sacs called alveoli. The alveoli are responsible for the primary function of the lungs, which is exchanging carbon dioxide and oxygen.

The bronchial tree has 27 generations beyond the main bronchi- the first 19 are conducting airways as far as terminal bronchiole. This muscular wall can change the size of the tubing to increase or decrease airflow through the tube.

Fig: Bronchial Tree

The divisions are as follows:

  • Trachea
  • Right & left principal bronchus
  • Lobar bronchus (3 for a right, 2 for left)
  • Segmental bronchus (10 in each lung)
  • Terminal bronchus Terminal bronchiole (after 9-12 generation of branching each divides into 5-7 respiratory bronchioles)

(Above all are a Conductive part)

(Below all are a Respiratory part)

  • Respiratory bronchiole
  • Alveolar duct
  • Atria
  • Alveolar sac
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