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.
Bronchi are the main passageway into the lungs. When someone takes a breath through their nose or mouth, the air travels into the larynx.The next step is through the trachea, which carries the air to the left and right bronchus.The bronchi become smaller the closer they get to the lung tissue and are then considered bronchioles.he next step is through the trachea, which carries the air to the left and right bronchus. The bronchi become smaller the closer they get to the lung tissue and are then considered bronchioles.