Draw the pathway of air trom nostils to lungs
Answers
The Human Respiratory System
The Pathway
Air enters the nostrils
passes through the nasopharynx,
the oral pharynx
through the glottis
into the trachea
into the right and left bronchi, which branches and rebranches into
bronchioles, each of which terminates in a cluster of
alveoli
Only in the alveoli does actual gas exchange takes place. There are some 300 million alveoli in two adult lungs. These provide a surface area of some 160 m2 (almost equal to the singles area of a tennis court and 80 times the area of our skin!).
Breathing
In mammals, the diaphragm divides the body cavity into the
abdominal cavity, which contains the viscera (e.g., stomach and intestines) and the
thoracic cavity, which contains the heart and lungs.
The inner surface of the thoracic cavity and the outer surface of the lungs are lined with pleural membranes which adhere to each other. If air is introduced between them, the adhesion is broken and the natural elasticity of the lung causes it to collapse. This can occur from trauma. And it is sometimes induced deliberately to allow the lung to rest. In either case, reinflation occurs as the air is gradually absorbed by the tissues.
