creatinine is a normal waste product produced by muscle metabolism when your kidneys are functioning normally they filter creatinine and other waste products out of your blood and send them out of the body through urine
Tweet. This follows the page describing the basic anatomy of the lower respiratory tract. The term  tracheobronchial tree  or  respiratory tree  refers to the structures of bronchi and bronchioles that terminate with the alveolar ducts, sacs, and, finally, alveoli-that are contained within the lungs.herefore these structures are also referred to as  airways . This pages includes two diagrams of the airways-the main structure of the tracheobroncial tree being shown immediately below, and a second diagram showing the alveoli in further detail further down the page.
The lungs are a pair of spongy, air-filled organs located on either side of the chest (thorax). The trachea (windpipe) conducts inhaled air into the lungs through its tubular branches, called bronchi. The bronchi then divide into smaller and smaller branches (bronchioles), finally becoming microscopic. Lung cancer: Cancer may affect almost any part of the lung. 2  Most lung cancer is caused by smoking. 3  Tuberculosis: A slowly progressive pneumonia caused by the bacteria Mycobacterium tuberculosis. 4  Chronic cough, fever, weight loss, and night sweats are common symptoms of tuberculosis.