When Abby Ellstrom and her friends at East High School in Denver crave classic chicken nuggets for lunch, the sophomores swipe the Uber icon on one of their smartphones and ride the nine blocks to Chick-fil-A.When they are done, they click Uber again for pickupâand make it back in time for their next class.y. When Abby Ellstrom and her friends at East High School in Denver crave classic chicken nuggets for lunch, the sophomores swipe the Uber icon on one of their smartphones and ride the nine blocks to Chick-fil-A. When they are done, they click Uber again for pickupâand make it back in time for their next class.
Trachea and Bronchi. The respiratory tree (figure 7-4) is the set of tubular structures which carry the air from the larynx to the alveoli of the lungs. Looking at a person UPSIDE DOWN, the trachea is the trunk of the tree and the bronchi are the branches. These tubular parts are held open (made patent) by rings of cartilage. Their lining is ciliated to remove mucus and other materials that get into the passageway.
Lung alveoli are the ends of the respiratory tree, branching from either alveolar sacs or alveolar ducts, which like alveoli are both sites of gas exchange with the blood as well. Alveoli are particular to mammalian lungs. Different structures are involved in gas exchange in other vertebrates. The alveolar membrane is the gas exchange surface. Carbon dioxide rich blood is pumped from the rest of the body into the capillaries that surround the alveoli where, through diffusion, carbon dioxide is released and oxygen absorbed.