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Fig. 246. Alimentary tube of a human embryo of 4.1 mm

His Kollmann.

As development proceeds, this simple tube elongates rapidly and becomes differentiated into distinct regions. The cephalic end, in connection with the branchial arches and grooves, becomes the dilated pharyngeal region. Caudal to and continuous with this, is the short, narrow cesophageal region which in turn passes over into the slightly dilated stomach region. The portion of the gut caudal to the stomach is the intestinal region. During the differential changes, the communication with the yolk sac becomes relatively smaller, forming the yolk stalk which joins the intestinal portion a short distance caudal to the stomach (Figs. 246 and 247)

--MarkHill 12:20, 15 April 2011 (EST) Staging is probably Carnegie stage 13 to 14 at the end of week 4 and beginning week 5, with some artistic licence.

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