Listed below are links to selected regions of the Stage 22 embryo that relate to the gastrointestinal tract. There are associated low power images showing where region has been selected from entire sections through the embryo.
Clicking on the section number will open the full image.
E3,E4: Central veins of liver. Radiating appearance of hepatic sinusoids.
E5: Central vein with endothelial lining, containing nucleated erythrocytes (haemopoietic role of fetal liver).
E6,E7: Pyloroduodenal junction. Note tall columnar entodermal cells, submucosa, muscularis externa with inner spiral, outer longitudinal smooth muscle. Tunica serosa.
Fl,F2: Pancreas and pancreatic duct joining duodenum. Superior mesenteric vein crossing cranial to pancreas. Note folds of duodenal mucosa.
G5-G7: Rectocolic junction. Mesocolon. Note layers of wall.
Please note that this is only a very quick sketch (took 10min). When I have some time I will include a proper labelled movie. Hope this is of some help. You can step through the images using the left-hand controls.
View from left hand side of embryo facing left. Sequence spans approx 6-11 weeks of development. There is an initial 90 degree rotation followed by 2 more 90 degree rotations to give 270 degrees total. The upper GIT is shader light green, the red vessel is the superior mesenteric artery off the dorsal aorta.