ABSTRACT
Uptake, transport, and delivery of oxygen to tissues are essential in maintaining physiologic integrity and cell viability. Concurrent removal of metabolic by-products including carbon dioxide from tissues is equally critical to maintain homeostasis. Because these processes have a common purpose, they are frequently linked together and referred to as respiratory gas transport. The process of transporting oxygen from the external environment to the cell is elegantly simple in concept but complex in practice. The respiratory system is comprised of several anatomic regions that blend together to facilitate gas transport to the alveolus. Gas transport and distribution begins at the nares and ends with gas delivery to the pulmonary alveolus. Pulmonary gas exchange requires metabolic energy to perform. Under normal conditions, lung expansion occurs in concert with chest wall and diaphragm motion.
