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Fig. 286. Transverse section of a 14 mm. pig embryo, at the level of the upper limb buds, showing especially the two bronchi

As has been stated, the caudal end of the original tube evaginates to form two hollow buds which are the beginnings. of the two lungs (Fig. 286). The evagination takes place soon after or even along with the separation of the lung groove from the gut. The right bud soon gives rise to three secondary buds, the forerunners of the three lobes of the right lung. The left bud gives rise to two secondary buds, the forerunners of the two lobes of the left lung (Fig. 287). The primary buds may be said to represent the two bronchi arising from the trachea, the five secondary buds to represent the bronchial rami which extend into the five lobes of the lungs. Successive evaginations from each of the five buds take place and form an extensive arborization for each lobe (Figs. Fig. 288 and Fig. 289).

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Bailey FR. and Miller AM. Text-Book of Embryology (1921) New York: William Wood and Co.

Cite this page: Hill, M.A. (2024, June 16) Embryology Bailey286.jpg. Retrieved from

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current22:10, 23 January 2011Thumbnail for version as of 22:10, 23 January 2011842 × 481 (85 KB)S8600021 (talk | contribs){{Template:Bailey 1921 Figures}} Category:Human Category:Respiratory