The human respiratory system is a series of organs responsible for taking in oxygen and expelling carbon dioxide. The primary organs of the respiratory system are lungs, which carry out the exchange of gases as we breathe. Red blood cells collect oxygen from the lungs and carry it out to parts of the body where it is needed. During the process, the red blood cells collect the carbon dioxide and transport it back to the lungs, where it leaves the body when we exhale. This seemingly simply process poses various danger as there may be invasive influences i.e. harmful foreign particles in the air we inhaled. A normal person inhales more than 2,000 gallons of air every day, but alongside dust, pollen, miscellaneous chemical substances, there are also various viruses and bacteria that may induce devastating conditions. Other than the lungs, the respiratory systems is also comprised of the respiratory tract i.e. nasal, larynx, trachea and bronchi. With each breath the immune function of the respiratory system operates in tandem to ensure that no harmful foreign substances reach the lungs. One example of such protection is the follicular phagocytosis which acts like a “garbage collector” removes harmful microorganism before they enter the lungs.

Respiratory diseases are associated with bacterial and viral infections. Severe cases included pneumonia, tuberculosis and specific allergic reactions. Common respiratory diseases include the common cold, epidemic flu, hay fever, bronchitis, pneumonia, asthma and streptococcal infections.