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.
The trachea â the tube connecting the throat to the bronchi. The bronchi â the trachea divides into two bronchi (tubes). One leads to the left lung, the other to the right lung. Inside the lungs each of the bronchi divides into smaller bronchi. The broncheoli - the bronchi branches off into smaller tubes called broncheoli which end in the pulmonary alveolus.