Where air enters the body.
In this part of the respiratory tract there are certain cells with vibrating filaments know as cilia.
Larynx
The walls of this tube are formed of cartilage that continually keeps it open.
It has open cartilage rings at its back.
On the sides of this airway there are tonsils, which produce white blood cells.
Bronchi
Pharynx
The presence of nooks and crannies in this section of the respiratory tract increases the lenght of the journey air goes within the body, making it warmer.
This area is common to the respiratory and digestive tracts. Foods continue their journey into the esophagus, while air passes into the larynx.
It's about 12 cm long.
In the first section, the internal wall has several capillaries, which warm up the air because they carry blood.
They branch into progressively smaller ducts.
There's mucous present in the interior of this section that traps foreign particles in the air.
Trachea
Nasal cavity
They are two airways.
They don't have cartilage rings.
They end in tiny sacts, called pulmonary alveoli.
Each tube enters a different lung.
In this section, air is purified and humidified.
Bronchioles
Entry to this area is regulated by a fibrous structure known as the epiglottis, which closes when food is being ingested to prevent the organism from choking or suffocating.