Zoology - Breathing and Exchange of Gases Question with Solution | TestHub

Trachea : It is a straight tube that extends upto the mid-thoracic cavity and divides at the level of 5^ththoracic vertebra into 2 branches: a right and left primary bronchi.

Branching in trachea leads to primary bronchi$\to$secondary bronchi$\to$tertiary bronchi and bronchioles$\to$terminal bronchioles$\to$alveoli (numerous very thin, irregular-walled and vascularised bag-like structures).

The tracheae, bronchi (primary, secondary and tertiary) and initial bronchioles are supported by incomplete cartilaginous rings.