The nose filters, warms and humidifies incoming air.
The mouth has a role in warming and humidifying air, and provides less resistance than the nose to air being inhaled or exhaled.
Warms, filters and humidifies the air, protects the lower airways during swallowing, permits speech and participates in the cough mechanism.
Is approximately 12 cm in length and 2.5cm in diameter. It is located in front of the oesophagus (food pipe), and extends from the Larynx to the junction of the right and left main bronchus.
The right main bronchus leads to the right lung. The left main bronchus leads to the left lung. These are the largest airways in the lungs.
The bronchioles branch off the two main bronchi like twigs off the branch of a tree. There are thousands of bronchial branches that form the network of airways that carry air into and our of the lungs.
Each person has two lungs, with the exception of those who have had operations. The right lung has three lobes and the left lung has two lobes, to allow space for the heart.
Two protective membranes, separated by the pleural space, surround the lungs. Inflammation of these membranes may cause sharp stabbing chest pain.
The alveoli are attached to the end of the bronchioles. They form tiny grape-like clusters. The average lung has approximately 300 million alveoli. Alveoli are the structures involved in gas exchange. This is where oxygen crosses into the bloodstream and carbon dioxide back into the lungs to be exhaled.
Tiny blood vessels (about 0.008mm in diameter), they are found in all the tissues of our body.
The rib cage protects the heart and lungs and also has a major role in the mechanics of breathing.
THE DIAPHRAGM AND INTERCOSTAL MUSCLES
These are the primary muscles of respiration; the diaphragm is dome shaped and sits under the lungs. The intercostals are found between the ribs.
The respiratory centre is located in the brain; it controls the rate and depth of breathing and responds to changes in levels of carbon dioxide and oxygen in the blood, triggering changes in respiration.