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.
The bronchi are two tubes that branch off the trachea, or windpipe. The bronchi carry air to your lungs. The most common problem with the bronchi is bronchitis, an inflammation of the tubes. Bronchitis can be acute or chronic.