How does the structure of The Respiratory System help it to function?

the thoracic cavity is an air tight chamber. the inhalation and exhalation occurs due to the pressure difference. when the external intercostal muscles contract the volume of the thoracic cavity increases thereby decreasing pulmonary air pressure and the atmospheric air enters the lungs. when the internal intersostal muscles contract the volume of the thoracic cavity decreases and the pulmonary pressure exceeds the atmospheric pressure and exhalation takes place. the nasal pathway and the trachea are lined with hair which removes foreign particles and the entire respiratory tract is lined with mucus to moisten the air and bring it to the body temperature.

the bronchioles end with tiny air sacs called alveoli which has an extremely thin wall. the alveoli is lined with blood capillaries and this is where gaseous exchange takes place. gaseous exchange occurs due to concentration gradient of the gas. when we inhale concentration of oxygen is greater in the lungs than in the capillaries so the oxygen molecules diffuse through the alveolar membrane to the blood capillaries and at the same time the concentration of carbon dioxide is greater in the capillaries than in the lungs so the carbon dioxide molecules diffuse into the lungs and are exhaled out.

i've assumed that you know the structure of the respiratory system. if not refer http://www.teachpe.com/anatomy/respiratory_system....

Trachea is your windpipe it includes mucus and cilia which traps dirt and micro organism. rings of cartilage save the trachea open so it would not close over on itself. Epiglottis is a flap of gristle which closes once you swallow so meals or liquid would not enter your lungs. Pleural membranes are for lubrication Intercostal muscle groups are used for respiration out and in. Bronchus divides into 2 optimum to the two lungs Bronchioles carry air to alveoli Alveoli around shape for significant floor are additionally skinny, permeable and moist for gas substitute