Question

Trace a molecule of oxygen from the time it enters the nasal cavity to its end point in the alveoli. Be sure to describe the function of each of the structures involved in this process.

Answer 1

As the molecule of oxygen enters the nasal cavity,(a function of the nasal cavity- it helps to purify the air and help to eliminate any foreign particles from the air before it reaches inside the body).

The molecule of oxygen travels through the pharynx (Function -it allows the molecule of oxygen which enters the nasal cavity to make through respiratory tract ) and then through the larynx and then it goes into the trachea. The vital function of the trachea is to provide to and fro movement of air during inspiration(air inside the lung) and expiration( air out of the body).

Then the trachea bifurcates in two bronchi which enter the left and right lung. The molecule of air travels through the trachea and reaches the primary bronchi(which is present in the lungs). The function of bronchi is to act as a carrier which carries an oxygen molecule to alveoli.

Primary bronchi branches into the primary bronchus. Primary bronchus further divides into bronchioles (which are smaller than bronchus). The bronchioles are also called respiratory bronchioles which are attached to alveolar ducts which further leads to alveolar sacs. Each alveolar sac contains approximately 20 - 30 alveoli. Alveoli play an important role in the gaseous exchange, alveoli are connected with capillary, and from here the exchange of oxygen/carbon dioxide happens