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.
Asthma in Cats. Asthma with Bronchitis in Cats. The lower respiratory tract, or lower airways, includes the bronchi, bronchioles, and alveoli. The bronchi begin at the end of the trachea, where they split off into two branches. From there they split off into smaller branches, called the bronchioles.