File:Gray0473.jpg

Fig. 473. Scheme of the Aortic Arches and their Destination

Modified from Julius Kollmann (1834 - 1918)

Recent observations show that practically none of the main vessels of the adult arise as such in the embryo. In the site of each vessel a capillary network forms, and by the enlargement of definite paths in this the larger arteries and veins are developed. The branches of the main arteries are not always simple modifications of the vessels of the capillary network, but may arise as new outgrowths from the enlarged stem.

It has been seen (page 506) that each primitive aorta consists of a ventral and a dorsal part which are continuous through the first aortic arch. The dorsal aortæ at first run backward separately on either side of the notochord, but about the third week they fuse from about the level of the fourth thoracic to that of the fourth lumbar segment to form a single trunk, the descending aorta. The first aortic arches run through the mandibular arches, and behind them five additional pairs are developed within the visceral arches; so that, in all, six pairs of aortic arches are formed (Figs. 472, Fig. 473). The first and second arches pass between the ventral and dorsal aortæ, while the others arise at first by a common trunk from the truncus arteriosus, but end separately in the dorsal aortæ. As the neck elongates, the ventral aortæ are drawn out, and the third and fourth arches arise directly from these vessels.

In fishes these arches persist and give off branches to the gills, in which the blood is oxygenated. In mammals some of them remain as permanent structures while others disappear or become obliterated (Fig. 473).

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Gray's Images: Development | Lymphatic | Neural | Vision | Hearing | Somatosensory | Integumentary | Respiratory | Gastrointestinal | Urogenital | Endocrine | Surface Anatomy | iBook | Historic Disclaimer

Historic Disclaimer - information about historic embryology pages

Pages where the terms "Historic" (textbooks, papers, people, recommendations) appear on this site, and sections within pages where this disclaimer appears, indicate that the content and scientific understanding are specific to the time of publication. This means that while some scientific descriptions are still accurate, the terminology and interpretation of the developmental mechanisms reflect the understanding at the time of original publication and those of the preceding periods, these terms, interpretations and recommendations may not reflect our current scientific understanding.     (More? Embryology History | Historic Embryology Papers)

iBook - Gray's Embryology

iTunes link | iBooks Store Description - an extract of the embryology content from Anatomy of the Human Body By Henry Gray Philadelphia: Lea & Febiger, 1918. Releases First Edition - Jan 2012 Second Edition - March 2012 Repaired formatting and image display issues related to Pad rotated display and minor editing issues. Print length 169 pages, 41.6 MB, Language English. The current website also includes numerous images from this textbook, see Anatomy of the Human Body by Henry Gray and Category:Gray's 1918 Anatomy. Note the also Historic Disclaimer.

Reference

Gray H. Anatomy of the human body. (1918) Philadelphia: Lea & Febiger.

Cite this page: Hill, M.A. (2024, April 27) Embryology Gray0473.jpg. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/File:Gray0473.jpg

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