ABSTRACT
Study objectives Describe the blood-gas interface and explain why the lungs are ideally suited for gas exchange List the components and the functions of the conducting airways Distinguish between the various types of airways in terms of epithelium and cartilage Describe the forces and factors responsible for maintaining ination of the lungs Explain how inspiration and expiration take place Distinguish between atmospheric pressure, alveolar pressure, intrapleural pressure, and transpulmonary pressure Dene pulmonary compliance Describe the role of elastic connective tissue in the elastic recoil of the lungs as well as in lung compliance Explain how surface tension affects the elastic behavior of the lungs Describe the functions of pulmonary surfactant Explain how interdependence promotes alveolar stability Describe the factors that determine airway resistance Dene tidal volume, residual volume, expiratory reserve volume, and inspiratory reserve volume Dene functional residual capacity, inspiratory capacity, total lung capacity, and vital capacity Distinguish between total ventilation and alveolar ventilation Distinguish between anatomical dead space, alveolar dead space, and physiological dead space Explain how each factor in Fick’s Law of Diffusion inuences gas exchange List the partial pressures of oxygen and carbon dioxide in the various regions of the respiratory and cardiovascular systems Explain how the PO2 and the PCO2 of the alveolar gas are determined Explain the effects of airway obstruction and obstructed blood ow on ventilation-perfusion (V/Q) matching Describe the local control mechanisms that restore the V/Q ratio to one Explain how oxygen is transported in the blood Describe the physiological signicance of the steep portion and the plateau portion of the oxyhemoglobin dissociation curve
•
• •
•
• •
• •
• • • • •
•
• •
•
•
• •
• • •
Describe the effects of carbon dioxide, pH, temperature, 2,3-bisphosphoglycerate, anemia, and carbon monoxide poisoning on the transport of oxygen Explain how carbon dioxide is transported in the blood Compare and contrast the functions of the dorsal and the ventral respiratory groups in the medullary respiratory center List and describe the sources of input to the medullary respiratory center Compare and contrast the function of the peripheral and the central chemoreceptors Describe the ventilation response to exercise
. Introduction The cells of the body require a continuous supply of oxygen to produce energy and carry out their metabolic functions. Furthermore, these aerobic metabolic processes produce carbon dioxide that must be continuously eliminated. Adequate removal of carbon dioxide is important in the regulation of acid-base balance, or concentration of H+ ion in the blood. Therefore, the primary functions of the respiratory system include obtaining oxygen from the external environment and supplying it to the body’s cells and eliminating from the body the carbon dioxide produced by cellular metabolism. The process by which oxygen is taken up by the lungs and carbon dioxide is eliminated from the lungs is referred to as gas exchange.
