Question

You are a molecule of oxygen floating happily through the atmosphere when all of a sudden you are inhaled by Ms Magenta.

Trace your pathway through Ms Magenta respiratory tract beginning in her nasal cavity to the point at which you cross the respiratory membrane and enter the pulmonary capillaries.

Answer 1

Answer is:

START nostrils > nasal cavity > pharynx > larynx > trachea > primary bronchus > secondary bronchi > tertiary bronchi > bronchioles > terminal bronchioles > respiratory bronchiole > alveolar duct > alveolar sac > alveoli > respiratory membrane > capillaries   END...

Explanation:

Molecule of oxygen from air passes through nasal cavity to the pharynx which is a throat and to the larynx which is a voice box. It makes a way to the trachea that funnels the inhaled air to lungs and exhale the air out of body.

The trachea secretes the mucus that catches inhaled air particles (molecular oxygen as given in question). It also has cilia that moves these particles toward the pharynx.

The end of trachea is divided into bronchi, thus air enters lungs through primary bronchi. The primary bronchus again divides into smaller bronchioles that spread through lung. The final bronchioles are respiratory bronchioles. Alveolar ducts attached to the end of respiratory bronchiole and at each duct there are alveolar sacs that contains alveoli. Gas exchange occurs in the alveoli that in direct contact with capillaries...