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.
Parts of the Respiratory System. THE HUMAN RESPIRATORY SYSTEM CONSISTS OF THE NOSE, NASAL CAVITY, PHARYNX, LARYNX, TRACHEA, SMALLER CONDUCTING PASSAGEWAYS (BRONCHI AND BRONCHIOLES), AND LUNGS.