. Human embryology and morphology. Embryology, Human; Morphology. THE EESPIRATOKY SYSTEM. 251 In the 4th week the pulmonary pocket produces a larger right and a smaller left process, the right and left lung buds. The median part, developed from the hinder end of the groove, grows out from the pharyngeal floor and forms the trachea. The groove in front forms the larynx. The right bud forms the right lung and bronchus; the left, the left lung and bronchus. The hypoblast becomes the epithelial lining of the respiratory tract; the surrounding mesoblast forms the vessels, connective- tissue coverin
. Human embryology and morphology. Embryology, Human; Morphology. THE EESPIRATOKY SYSTEM. 251 In the 4th week the pulmonary pocket produces a larger right and a smaller left process, the right and left lung buds. The median part, developed from the hinder end of the groove, grows out from the pharyngeal floor and forms the trachea. The groove in front forms the larynx. The right bud forms the right lung and bronchus; the left, the left lung and bronchus. The hypoblast becomes the epithelial lining of the respiratory tract; the surrounding mesoblast forms the vessels, connective- tissue covering and coats of the respiratory tubes and lungs. As the lung buds develop the stomach is forced backwards; the oesophagus becomes elongated. The tracheal part of the bud becomes separated from the oesophagus, but both retain the same nerve supply—the recurrent branch of the vagus—which is the nerve of the 5 th arch. right dorsal aorta fore-gut right lung bud dorsal mesocard. passage between pericard. and pleura. left dorsal aorta dorsal mesent. card, uein of left side -f-pleuro-perit. eommun pleura uen. mesocard. left d. of Cuuier pericard. heart pericardium Fio. 205.—A section of a human embryo to show the Relationships oJ the Pulmonary Buds at the 4th week, looking backwards. (After Kollmann.) In Fig. 205 the relationship of the lung buds is shown to surrounding structures during the 4 th week. The following points should be noted: (1) As the lung bud grows out it pushes its way into the isthmus of the coelom—the narrow neck of communication between the pericardium and peritoneum (Fig. 201). This part. 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 Keith, Arthur, Sir, 1866-1955. London : E. Arnold
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectembryol, bookyear1902
