The mechanism by which organisms obtain oxygen from the environment and release Carbondioxide, is termedasBreathing.
-- In human beings, air is taken through the nostrils. The entire nasal passage is lined with mucus which help in the filtration of air . From nostrils, the air pases through the throat and ultimately into the lungs.
Rings of cartilage are present in the throat which ensure that the air passage does not collapse.
within the lungs , the bronchi divides into bronchioles and bronchioles called alveoliwhich provide larger surface where exchange of gases can take place.
The walls of alveoli contain an extensive network of blood vessels which help in easier transportation of gases to all the cells in the body.
During breathing ribsgetsraisedwhichflattenthediaphragmresultinginlargerchestcavity.Due to this , air is sųcked into the lungs and fills the expanded alveoli ( Inhalation ).
During the breathing cycle , when air is taken in and let out ( exhalation), the lungs always contain a residual volume of air so that there is sufficient time for oxygen to be absorbed and for the Carbondioxide to be released.
