The respiratory system consists of several parts:
1. the upper airways
2. the lungs (left and right)
3. the blood vessels
4. the chest wall
5. the brain
The task of the respiratory system is to get fresh air, especially oxygen (O2), into the lungs and to get rid of the gaseous waste, carbon dioxide (CO2), that we are constantly producing (with our metabolism).
The upper airway transports the air between the outside world and the lungs. It consists of:
1. the nose (nasal cavity)
2. the mouth (oral cavity)
3. the pharynx
4. the larynx
5. the trachea
6. the bronchial tree
The lungs are the organs where fresh air gets very close to the blood. This occurs in the alveoli (singular: alveolus), at the end of the bronchial tree. In this location, the gas exchange between air and blood occurs.
So, the respiratory system also needs arteries to bring oxygen-poor blood to the lungs and veins to take oxygen-rich blood away from the lungs. This blood is pumped, through the lungs, by the right heart (link see CVS).
Crucial for a proper functioning of the respiratory system is the chest wall and the diaphragm. These can expand and contract, thereby expanding the size of the chest, which, in turn, expand or constrict the lungs.
Finally, in contrast to the heart, which has its own pacemaker, the lungs are not automatic; they don’t have a pacemaker. Instead, the “pacemaker” of the lungs is located in the brain, in the brain stem. Without your brain, no respiration!
B. Do you remember how an old-fashioned air bellow works?