The components of the respiratory system (F. Martini, A&P, 2004) The respiratory epithelium of the nasal cavity and conducting system (F. Martini, A&P, 2004) The nose (a) and nasal cavity (b) (F. Martini, A&P, 2004) The pharynx (F. Martini, A&P, 2004) The anatomy of the larynx (F. Martini, A&P, 2004) The glottis (a) A diagrammatic superior view of the entrance to the larynx, with the glottis open (left) and closed (right). (b) A fiber optic view of the entrance to the larynx, corresponding to the right-hand image in part (a). Note that the glottis is almost completely closed by the vocal folds. (F. Martini, A&P, 2004) The anatomy of the trachea (F. Martini, A&P, 2004) The gross anatomy of the lungs (F. Martini, A&P, 2004) The bronchioles (a) The distribution of a respiratory bronchiole supplying a portion of a lobule. (b) Alveolar sacs and alveoli (LM X 42). (c) An SEM of the lung, showing the spongy appearance of the lung tissue (F. Martini, A&P, 2004). Alveolar organization (a) The basic structure of a portion of a single lobule. A network of capillaries, supported by elastic fibers, surrounds each alveolus. Respiratory bronchioles also contain wrappings of smooth muscle that can change the diameter of these airways. (b) A diagrammatic view of alveolar structure. A single capillary may be involved with gas exchange across several alveoli simultaneously. (c) The respiratory membrane, which consists of an alveolar epithelial cell, a capillary epithelial cell, a capillary endothelial cell, and their fused basal laminae (F. Martini, A&P, 2004). An overview of key steps in respiration (F. Martini, A&P, 2004) Mechanisms of pulmonary ventilation (a) As the ribs are elevated or the diaphragm is depressed, the volume of the thoracic cavity increases. (b) An anterior view with the diaphragm at rest, with no air movement. (c) Inhalation: Elevation of the rib cage and contraction of the diaphragm increase the size of the thoracic cavity. Pressure decreases, and air flows into the lungs. (d) Exhalation: When the rib cage returns to its original position, the volume of the thoracic cavity decreases. Pressure rises, and air moves out of the lungs. (F. Martini, A&P, 2004) Pressure changes during inhalation and exhalation These graphs follow changes in the (a) intrapulmonary and (b) intrapleural pressures during a single respiratory cycle and related the changes to (c) the tidal volume. (F. Martini, A&P, 2004). The respiratory muscles (a) Movements of the ribs and diaphragm that increase the volume of the thoracic cavity. (b) Anterior view at rest, with no air movement showing the primary and accessory respiratory muscles. (c) A lateral view during inhalation, showing the muscles that elevate the ribs. (d) A lateral view during exhalation, showing the muscles that depress the ribs. The abdominal muscles that assist in exhalation are represented by the single muscle (rectus abdominis) (F. Martini, A&P, 2004) Respiratory volumes and capacities (F. Martini, A&P, 2004) An overview of respiratory processes and partial pressures in respiration (a) Partial pressures and diffusion at the respiratory membrane. (b) Partial pressures and diffusion in other tissues. (F. Martini, A&P, 2004) The oxygen-hemoglobin saturation curve (F. Martini, A&P, 2004) The effects of ph and temperature on hemoglobin saturation (a) When the ph drops below normal levels, more oxygen is released; the hemoglobin saturation curve shifts to the right. If the ph increases, less oxygen is released; the curve shifts to the left. (b) When the temperature rises, the saturation curve shifts to the right (F. Martini, A&P, 2004). Carbon dioxide transport in blood (F. Martini, A&P, 2004) Gas transport mechanisms (a) Oxygen transport. (b) Carbon dioxide transport (F. Martini, A&P, 2004). Respiratory centers and reflex controls The position of the major respiratory centers and other factors important to the reflex control of respiration. Pathways for conscious control over respiratory muscles are not shown. (F. Martini, A&P, 2004) Aging and the decline in respiratory performance The relative respiratory performances of individuals who have never smoked, individuals who quit smoking at age 45, individuals who quit smoking at age 65, and lifelog smokers (F. Martini, A&P, 2004).