The respiratory tract plays a crucial role in sustaining life by performing several essential functions related to breathing and gas exchange:

1. Gas Exchange: The primary function of the respiratory tract is for exchange of gases, oxygen, and carbon dioxide. Oxygen is inhaled into the lungs and carbon dioxide, a waste product of metabolism, is exhaled.
2. Prevent aspiration: During swallowing, the epiglottis/vocal cord closes the trachea.
3. Voice Production: The vocal cord located in the upper respiratory tract enables speech use for communication and production of sound.
4. Protection: The respiratory tract (RT) has several defence mechanisms to protect against pathogens and harmful substances. The layer of mucus and cilia in the airways, traps and removes debris out of the lungs. Additionally, reflexes like coughing and sneezing help expel irritants from the respiratory system.

Olfaction (Sense of Smell): The nasal cavity contains olfactory receptors that detect odours, contributing to the sense of smell, which is important for taste, detection of hazards, and environmental awareness.