Most WHO departments have their own procedures for supporting research in priority areas-these vary from requesting letters of intent to issuing a call for proposals to commissioning research.
In humans and other mammals, the anatomical features of the respiratory system include trachea, bronchi, bronchioles, lungs, and diaphragm. Molecules of oxygen and carbon dioxide are passively exchanged, by diffusion, between the gaseous external environment and the blood.
this Article. Diseases of the respiratory system occur primarily in the bronchioles and the alveoli. Much rarer, unless you count choking and drowning, are conditions that affect the larger passageways of the lungs such as the trachea and the bronchi.