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

Cartilaginous ring structures are found the tubes of the respiratory system to prevent its collapse. It is present in the trachea, two initial branches of bronchi along with the secondary and tertiary bronchi. The initial bronchioles also have it. The terminal bronchioles are not having any rings and they give rise to number of thing vascularized structures called alveoli. The terminal bronchi is also called as the respiratory bronchioles.