. The comparative physiology of respiratory mechanisms. Respiration. RESPIRATION IN AIR 63 made, and a fairly probable figure is 90 m2 for a volume of 3 1 or 300 cm2 per cubic centimeter. In the lung of the frog the capillary area is about 2/3 of the total surface. In man it would appear to represent even a larger Fig. 36. Diagram of Rana lung* with complex septa. (Renault.) * In the species of Rana known to the writer the septa are more simple. Fig. 37. Diagram of Testudo lung with simple bronchial air passages. (Renault.) In many reptiles (Wolf, 1933), and especially in snakes,
. The comparative physiology of respiratory mechanisms. Respiration. RESPIRATION IN AIR 63 made, and a fairly probable figure is 90 m2 for a volume of 3 1 or 300 cm2 per cubic centimeter. In the lung of the frog the capillary area is about 2/3 of the total surface. In man it would appear to represent even a larger Fig. 36. Diagram of Rana lung* with complex septa. (Renault.) * In the species of Rana known to the writer the septa are more simple. Fig. 37. Diagram of Testudo lung with simple bronchial air passages. (Renault.) In many reptiles (Wolf, 1933), and especially in snakes, considerable parts of the lungs have no respiratory epithelium and only a poor blood supply which is, moreover, often ar- terial. In the birds these "air-sacs" reach their highest de- velopment and will be discussed in a separate section. The functions of the air-sacs in reptiles are very imperfectly understood. With the exception of the birds and a few mammals (ele- phants), in which the lungs adhere firmly to the ribs, each lung is freely suspended in a "pleural" cavity and connected with the rest of the body only through the hilus, where the main bronchus, the pulmonary artery and vein and the pulmonary nerves enter its substance. The lungs are highly elastic, and in most cases they will contract and drive out most or all of the air contained when the glottis is open and air is admitted. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Krogh, August, 1874-1949. Philadelphia, University of Pennsylvania press
Size: 1801px × 1388px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookcollectionbiodivers, booksubjectrespiration
