DEV2022 Study Guide - Final Guide: Fetus, Bronchiole, Alveolar Cells
Document Summary
Human lungs are located in two cavities on either side of the heart, however they are not identical. Both lungs are separated into lobes by fissures, with 3 lobes on the right and 2 on the left. Each lobe is surrounded by a pleural cavity, which consists of 2 pleurae. The parietal pleura lies against the rib cage, and the visceral pleura lies on the surface of the lungs. The pleural cavity helps lubricate the lungs, as well as provide surface tension to keep the lung surface in contact with the rib cage. Their principle function is to transport oxygen from the atmosphere into the bloodstream, and to release carbon dioxide from the bloodstream into the atmosphere. A large surface area is needed for this exchange of gases which is accomplished by specialized cells that form thin-walled air sacs, alveoli. In humans, the trachea divides into the two main bronchi that enter the roots of the lungs.
