Human respiratory system

Respiration is one of the metabolic processes which play an essential role in all living organisms. When we breathe, we inhale oxygen and exhale carbon dioxide. The process so-called exchange of gases is necessary for respiration and which can be considered as a chemical process.

Every organism, from an individual bacteria cell to a mighty blue whale, undergoes respiration.
The human respiratory system consists of the following parts:

• External nostrils – For the intake of air.
• Nasal chamber – which is lined with hair and mucus to filter the air and remove dust and dirt.
• Pharynx – It is a passage behind the nasal chamber and serves as the common passageway for both air and food.
• Larynx – Also known as the sound box as it helps in the generation of sound and thus helps us in communicating.
• Epiglottis – It is a flap-like structure that covers the glottis and prevents the entry of food into the windpipe.
• Trachea – It is a long tube passing through the mid-thoracic cavity.
• Bronchi – The trachea divides into left and right bronchi.
• Bronchioles – Each bronchus is further  divided into finer channels known as bronchioles.
• Alveoli – The bronchioles end up into the balloon-like structures known as the alveoli.
• Lungs – We have a pair of lungs, which are sac-like structures and covered by a double-layered membrane known as pleura.