The Respiratory System
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Functions
Defenses
Tissues
Structures
Respiratory Tract
Gas Exchange
Disorders
Trachea
The start of the lower respiratory tract is the trachea.
Primary Bronchi
The trachea branches into two primary bronchi. (Left and Right).
Lungs
Each of the primary bronchi branch into a lung.
Secondary/Tertiary Bronchi
In each lung, the primary bronchi branch into many secondary and tertiary bronchi.
Bronchioles
The secondary and tertiary bronchi branch into many different bronchioles.
Alveoli
Finally, the bronchi branch into millions of alveoli which are the site of gas exchange.
Home
Functions
Defenses
Tissues
Structures
Respiratory Tract
Gas Exchange
Disorders