Occupational Safety and Health Administration. 1  Department of Labor, Labor Department, DoL, Labor - the federal department responsible for promoting the working conditions of wage earners in the United States; created in 1913.
The oxygen and carbon dioxide exchange take place in the alveoli. Primary bronchi are located on the upper portion of the lungs, secondary bronchi is located at the center of the lungs and tertiary bronchi is located near bottom of the organs above the bronchioles.
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.