It is important to learn about the respiratory system because this is the system that you will most likely have to consider and treat in a medical emergency. This includes everyone from First Aiders to Intensive Care Doctors.
The Respiratory System involves all the pipes and conducting airways from the mouth through to the lungs, including: mouth, larynx, trachea, right and left main bronchus (sides of the lungs), bronchioles (little branches of the lungs), alvioli (little sacs in which gasseous exchange takes place). After the respiratory system gets the oxygen to the alivioli, and gasseous exchange takes place, the circulatory system then removes CO2 from cells throughout the whole body, while O2 is delivered to all cells within the body.
Like all other piping systems, if you a pipe becomes blocked, no further flow (in this case of oxygen) will progress. In the human body, a failure within the respiratory system can lead to death in about five minutes.