Overview of the canine airway and lungs, and the role of panting in gas exchange and in regulating body temperature.
General educational reference only — not clinical or veterinary advice. Anatomy varies between individual animals; consult a licensed veterinarian for any health concern.
Upper airway
Air enters through the nostrils and nasal passages, which warm, humidify, and filter it. The dog's nasal cavity has an extensive turbinate structure linked to a highly developed sense of smell. Air then passes through the pharynx and larynx, which also guards the airway during swallowing.
Lower airway and lungs
From the larynx, air travels down the trachea, which branches into bronchi and progressively smaller bronchioles. These end in tiny air sacs called alveoli, where oxygen and carbon dioxide are exchanged with the blood. The lungs are divided into lobes and sit within the chest cavity.
Breathing and panting
The diaphragm and chest muscles drive breathing by changing the volume of the chest. Because dogs have limited sweat glands, panting — rapid, shallow breathing — is a key way they release heat by evaporating moisture from the mouth and upper airway. Brachycephalic (short-muzzled) breeds have a noticeably different upper-airway shape.
Sources
Veterinary anatomy and physiology texts; Merck Veterinary Manual (general reference)
