Respiratory system of dog
Respiration provides the dog’s body with the oxygen that is vital for life, and expels waste products in the form of nitrogen and carbon dioxide gases from the blood. Oxygen is carried around the body via the blood, enabling body cells to live and be renewed so that the dog can function.
Air passage – oxygen enters the dog’s body when he inhales through his nostrils and mouth, then it goes down the trachea (windpipe) and into the lungs. Waste gases exit the body via the same route in reverse when the dog exhales.
Key questions Is it normal for a dog to wheeze when breathing or should I be concerned?
Wheezing, or other abnormal sounds, when breathing indicate that something is wrong and should be investigated by a vet. Some overly exaggerated-type dogs in brachycephalic breeds (see opposite) are prone to breathing problems where the length of the nose is extremely short and nostrils are tiny.
Trachea – the trachea is a flexible, hollow f tube comprising 35 ring-shaped tracheal cartilages that prevent the tube from collapsing. To stop food, water and other objects (such as stones and toys) entering it via the mouth, and getting into the lungs, a valve called the larynx guards the entrance.
Respiration rate – how many times a dog inhales and exhales a minute depends on his size, age, environment and body temperature, general health and emotional state. Generally, a normal respiration rate is 10-30 breaths in 60 seconds. Small and young puppies breathe faster.
Brachycephalic breeds – such as Shih Tzus, Bulldogs and others with ‘squashed’ faces, wheeze in their efforts to draw in enough oxygen due to tiny nostrils and restricted, short nasal passages limiting their air intake.
Panting helps keep dogs cool. Drawing cold air in over the tongue and passing it out again reduces body heat by water evaporation from the tongue, lips, mouth cavity and lungs. However, dogs are prone
to overheating, which is why they should never be left unattended in vehicles on warm days – many dogs die every year because of this.