The 'airways' are those parts of the
respiratory system through which air flows, to get from the external environment to the
alveoli.
The airway begins at the mouth or nose, and accesses the
trachea via the
pharynx. The trachea branches into the left and right main
bronchi at the
carina, situated at the level of the second
thoracic vertebra. The bronchi branch into large
bronchioles, one for each
lobe of the
lung. Within the lobes, the bronchi further subdivide some 20 times, ending in clusters of alveoli.
The
epithelial surfaces of the airways contain
cilia. Inhaled particles stick to
mucus (secreted by goblet
cells) which is continuously removed from the airways by these cilia. The airway epithelium also secretes a watery fluid upon which the mucus can ride freely. The production of this fluid is impaired by the disease
cystic fibrosis.
Macrophages are present in the airways. These cells protect the airways from infection by engulfing inhaled particles and
bacteria.
Certain conditions require tracheal intubation to secure the airway.
Airway devices are used to assist
intubation.
External links
★
The Virtual Airway Device, a free resource about airway devices, including a video library