. Embryology. Embryology; Embryology; genealogy. 220 EMBRYOLOGY continuous cavity from the diencephalon through the optic stalk and into the optic cup. Most of the other structures are in about the same relationship as in Figure 137. In a still more posterior section the very beginnings of the olfactory placodes may be seen opposite the telencephalon (Fig. 139). Like the lens of the eye and the otocyst, they form as thickenings of the epidermis and invaginate. They do not, however, separate from the adjacent epidermis. The circulatory system in this region consists of the bulbus arteriosus, wi
. Embryology. Embryology; Embryology; genealogy. 220 EMBRYOLOGY continuous cavity from the diencephalon through the optic stalk and into the optic cup. Most of the other structures are in about the same relationship as in Figure 137. In a still more posterior section the very beginnings of the olfactory placodes may be seen opposite the telencephalon (Fig. 139). Like the lens of the eye and the otocyst, they form as thickenings of the epidermis and invaginate. They do not, however, separate from the adjacent epidermis. The circulatory system in this region consists of the bulbus arteriosus, with its thick-walled epimyocardmm and its thin-walled endothelium. A short ventral aorta communicates (in other sections) with the third aortic arches and these in turn run up through the visceral arches to join the dorsal aortae. The cardinal veins are more ventral and lateral compared to their position in previously described sections. From the floor of the pharynx a clear, V-shaped thyroid evagination is seen. Mesodermal somites are present opposite the myelencephalon. The section shown in Figure 140 passes through the developing liver buds. These are outgrowths of the wall of the gut at the region where the vitelline veins join before entering the sinus venosus of the heart. The liver EPIMYOCARDIUM OLFACTORY PLACODE TELENCEPHALON. ENDOCARDIUM ANTERIOR CARDINAL VEIN DORSAL AORTA THYROID Fig. 139. The olfactory placodes, bulbus arteriosus, and thyroid evaginat of a 48-hour chick embryo. ion FOREGUT EMBRYONIC COELOM. 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 Barth, Lester G. (Lester George), 1905-1979. New York, Dryden Press
Size: 2030px × 1231px
Photo credit: © Paul Fearn / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., boo, bookcentury1900, booksubjectembryology, booksubjectgenealogy
