How are the Alveoli Designed to Maximize the Exchange of Gases

Answer: The human airway is composed of the nasal passages, pharynx,  epiglottis, larynx, trachea, bronchioles, bronchi and lungs. In the lungs, oxygen is exchanged for carbon dioxide waste through millions of microscopic sacs known as alveoli. 

• The inhaled oxygen diffuses into the capillaries of the lungs, binds to haemoglobin and is sent into the bloodstream. 
• Carbon dioxide from the blood diffuses through the alveoli and is expelled by exhalation.  
• The alveoli have thin walls and a rich network of blood vessels that facilitate gas exchange between blood and the air filled in the alveoli.  
• They have a balloon-like structure that provides maximum surface area for gas exchange.