Aids to embryology / by J.S. Baxter.

  • James Sinclair Baxter
Date:
1948
Catalogue details

Licence: In copyright

Credit: Aids to embryology / by J.S. Baxter. Source: Wellcome Collection.

    101/204 page 89
    The primitive dorsal border of the stomach then becomes the greater curvature and the lesser curva- ture represents the primitive ventral border. The rapidly enlarging oesophageal end becomes the fundus. The dorsal mesentery attached to the stomach (more correctly called the dorsal mesogastrium) is influenced by the rotation of the stomach so that a blind retro- gastric recess is formed opening to the right. This corresponds in part with the lesser sac of peritoneum in the adult. Rapid growth of the dorsal meso- gastrium causes it to sag in a caudal direction and so form the primordium of the great omentum (see Fig. 22). The liver develops as an outgrowth from the primitive gut into the ventral mesentery, which becomes subdivided thus into two parts, the lesser omentum extending between the lesser curvature and the developing liver and the falciform and coronary system of peritoneal ligaments attaching the liver to the under surface of the diaphragm (derived largely from the septum transversum). At first the pyloric portion of the stomach forms almost half the total length, but the later, more rapid growth at the oeso- phageal end soon produces a stomach of more adult proportions. Pits in the entodermal lining develop about the middle of the second month, and the gastric glands commence to differentiate during the fourth month. At this time, some of the gland cells stain intensely with eosin and are considered to be the future parietal cells, while others remaining pale are designated as zygmogenic cells. Rennin and hydro- chloric acid have been demonstrated in the foetal stomach at the end of the fifth month, while pepsin is present somewhat earlier (Lucas Keene and Hewer). The Intestine.—The segment of gut caudal to the stomach grows rapidly and soon forms a loop convex ventrally. A vitelline vessel, the future superior mesenteric artery, runs from the dorsal aorta to the
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