. The comparative physiology of respiratory mechanisms. Respiration. RESPIRATION IN AIR 71 fly (Apteryx, Penguins) show these adaptations in a greatly reduced form. The lungs of birds are small and compact. They adhere firmly to the wall of the thorax, and a number of ribs are embedded in their substance (Fig. 42). L.«K^i3E. Fig. 43. Air-sacs of duck, inflated. (Sappey.) Certain large bronchi pass directly through the lungs and open through wide "ostia" into spacious air-sacs (Figs. 43, 44, 45). It is convenient to distinguish between the anterior sacs comprising the two cervical, th
. The comparative physiology of respiratory mechanisms. Respiration. RESPIRATION IN AIR 71 fly (Apteryx, Penguins) show these adaptations in a greatly reduced form. The lungs of birds are small and compact. They adhere firmly to the wall of the thorax, and a number of ribs are embedded in their substance (Fig. 42). L.«K^i3E. Fig. 43. Air-sacs of duck, inflated. (Sappey.) Certain large bronchi pass directly through the lungs and open through wide "ostia" into spacious air-sacs (Figs. 43, 44, 45). It is convenient to distinguish between the anterior sacs comprising the two cervical, the single clavicular, and the two praethoracic, and the posterior comprising the paired post- thoracic and abdominal. The air-sacs are very thin-walled and have only a poor supply of arterial blood. No significant exchange of gases takes place through their walls (Soum, 1896). The two main bronchi arising from the trachea lose their cartilage shortly after entering the lungs and continue as "mesobronchi" towards the posterior ends of the lungs, open- ing there into the abdominal sacs. From the main- and mesobronchi a definite small number of primary bronchi lead to the other air-sacs and into the "parenchyma" of the lungs (Fig. 45). The walls of all these bronchi and their ramifica- tions are pierced like a sieve by an enormous number of holes (about 1/2 mm wide) leading into "; The walls of these again are a meshwork and open into air-capillaries. 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
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Keywords: ., bookcentury1900, bookcollectionbiodivers, booksubjectrespiration
