In order to remain active, our body’s cells need oxygen. The respiratory system carries out this task through respiration, which is an involuntary process controlled by the respiratory centers found in the cerebral trunk.
It is activated by certain organs and structures such as the respiratory pathways or airways (nasal cavity, pharynx, larynx, trachea and bronchi) and the lungs.
After air reaches the lungs, the oxygen supply is transported by the blood in order to distribute it to all of the tissues in our body. At the same time, this system is in charge of expelling carbon dioxide from our body.
The main functions of the respiratory system are:
– Ventilation: the volume of the thorax changes depending on the muscle contractions that carry air into and out of the lungs.
– External respiration: the oxygen that enters our lungs passes on to the blood. On the other hand, carbon dioxide (which is produced by the cells) goes the opposite way; it goes from the inside to the outside of our body.
– Internal or cellular respiration: it is the exchange of gases that takes place between blood and tissues, a process responsible for the chemical changes that release energy and carbon dioxide (it passes from the cells to the blood).
Respiratory pathways are a set of organs (nasal cavity, pharynx, larynx, trachea and bronchi) that carry air to the lungs. Inside, they are coated by a layer of epithelial tissue (made up of very close-knit cells that barely have any intercellular substance between them, which protects the body from injuries and infections) and respiratory mucus. The function of this mucus is keeping the air that enters the lungs at the right temperature and humidity level.
Two different kinds of cells can be found on the surface of this tissue: mucosa, which produce and transport mucus towards the entrance of the airways, and cilia cells, which have cilia, tiny hairs that are in constant motion, managing to clean the surface of the lungs and removing particles stuck to the mucus.