LUNGS<br />Two compound saccular organs that constitute the basic respiratory organ of airbreathing vertebrates, that normally occupy the entirelateral parts of the thorax and consist essentially of an inverted tree of intricately branched bronchioles communicating with thin walled terminal alveoli swathed in a network of delicate capillaries where the actual gaseous exchange. <br />
The right lung has three lobes and the left lung has two.<br />
Function of respiration<br /><ul><li>Alter the PH of blood by facilitating alterations in the partial pressure of carbon dioxide.
Filter out gas micro-bubbles occuring in the venous blood stream such as those created after sccuba diving during decompression. </li></li></ul><li>FACTS<br /><ul><li>Total amount of air in the respiratory system is about 4 litres in a smaller adult, up to 6 litres.
About 1 litre of air always stays in the lungs no matter how hard we breathe out.
In an average lifetime a person takes around half a billion breaths.
In both lungs of an adult there are about 300 million alveoli.
If all the different- sized air tubes in the lungs could be joined end to end they would stretch more than 50km.</li>