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.
A bronchus is one of the large tubes that lead from the human trachea to the lungs. There is one large bronchus in each lung that branches out into smaller bronchi within the lungs. Bronchi carry air into and out of the lungs.The respiratory system begins at the nose and mouth, which meet at the pharynx.he right main bronchus is larger than the left. It divides into three lobar bronchi. The left main bronchus splits off into two lobar bronchi. The lobar bronchi then branch into what are called tertiary bronchi, and then into smaller bronchioles.