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.
Terminal Bronchi and Alveoli. The terminal bronchi and alveoli are located at the very end of the conducting zone and the beginning of the respiratory zone in the respiratory system. The bronchi (or bronchus) are the air passages into the lungs that begin at the end of the trachea. There are two bronchi, one for each lung.