2-2
2-2. THE RESPIRATORY SYSTEM
a. The cells of the body require a constant supply of oxygen to carry on the chemical processes necessary to life. As a result of these processes, carbon dioxide, a waste product, is formed, and must be removed from the body. Oxygen and carbon dioxide are continually being exchanged, both between the body and the atmosphere and within the body. This process is known as respiration, and the body system that performs this exchange of gases is the respiratory system.
b. The respiratory system is a continuous series of passages that begins with the nose and ends in the alveoli of the lungs. The upper respiratory system includes the nose, pharynx, larynx, and the trachea. The lower respiratory system includes the right and left bronchi, their subdivisions, and the lungs. Review Figure 2-1 as you read the next paragraph.
(Upper respiratory system)
(Lower respiratory system)
Figure 2-1. The human respiratory system.
