1 Be clear in what you are claiming. 2  Tell the reader which claims are based on facts and which on values. 3  Provide good evidence in support of your claim. 4  If a connection between the evidence and the claim is not obvious, tell the reader the connection.
Gas Exchange Between Alveolar Spaces and Capillaries. The function of the respiratory system is to exchange two gases: oxygen and carbon dioxide. The exchange takes place in the millions of alveoli in the lungs and the capillaries that envelop them. As shown below, inhaled oxygen moves from the alveoli to the blood in the capillaries, and carbon dioxide moves from the blood in the capillaries to the air in the alveoli.
Oxygen-carbon dioxide-The process by which oxygen passes from the air in the LUNGS to the HEMOGLOBIN in the BLOOD, and carbon dioxide from the hemoglobin passes into the air in the lungs. Oxygen-carbon dioxide exchange is fundamental to life and is the primary function of the lungs. Oxygen-carbon dioxide exchange takes place between the alveoli, the tiny bubblelike sacs deep within the lungs, and the capillaries, the tiniest blood vessels of the cardiovascular system.