Development of GI system http web nchu edu

Development of GI system 陳建榮 http: //web. nchu. edu. tw/pweb/index 2. php? pid=75

GI system: -Primitive Gut Morphogenesis -Foregut -Midgut -Hindgut -Foregut embryology -Midgut embryology -Hindgut embryology

Formation of primitive gut Head fold, tail fold and lateral fold -Foregut -Midgut -Hindgut

Primitive gut:

The primitive gut: -Foregut 前腸 -esophagus -stomach(S) -proximal half of the duodenum (PD), -liver and pancreas. -Midgut 中腸 -distal half of the duodenum(DD) -jejunum(J), -ileum(I), -cecum(C), -appendix, -ascending colon and the right 3/4 of the transverse colon. -Hindgut 後腸 -left 1/4 of the transverse colon -the descending colon -sigmoid colon -the rectum(R) down to the ano-rectal line (the endoderm-ectoderm junction).

The blood supply: -Foregut : celiac artery -Midgut : superior mesenteric artery -Hindgut : inferior mesenteric artery The venous drainage of the gut : -Foregut : portal vein -Midgut : superior mesenteric vein -Hindgut : inferior mesenteric vein.

Functional divisions of primitive GI system DIVISION PARASYMPATH ETIC VEIN LYMPHATICS SYMPATHETIC PORTAL VEIN Spleenic vein Gastric vein CELIAC NODES CELIAC GANGLIA VAGUS MIDGUT: l. Distal half of duodenum (from CBD) l. Jejunum SUPERIOR l. Ileum MESENTERIC l. Appendix ARTERY l. Cecum l. Ascending colon l. Right 3/4 of transverse colon SUPERIOR MESENTERIC VEIN SUPERIOR MESENTERIC NODES SUPERIOR MESENTERIC GANGLIA VAGUS HINDGUT: INFERIOR l. Left 1/4 of transverse colon MESENTERIC l. Descending colon ARTERY l. All of rectum down to ano-rectal line INFERIOR MESENTERIC VEIN INFERIOR MESENTERIC NODES GANGLIA HYPOGASTRIC PLEXUS PELVIC SPLANCHNIC NERVES FOREGUT: l. Esophagus l. Stomach l. Proximal half of duodenum (up to common bile duct (CBD)) l. Liver l. Pancreas ARTERY CELIAC ARETERY

GI system: -Primitive Gut Morphogenesis -Foregut Embryology -Development of stomach -Development of mesentery -Liver morphogenesis -Pancrease morphogenesis -Midgut embryology -Hindgut embryology

Development of stomach Stomach: -Clock wise 90 -Greater curvature of stomach胃大彎 -Lesser curvature of stomach胃小彎 -Vagus n.

Development of stomach

GI system: -Primitive Gut Morphogenesis -Mesentery morphogenesis -Dorsal mesentery背總腸繫膜 -Ventral mesentery腹總腸繫膜 -Foregut Embryology -Midgut embryology -Hindgut embryology

Formation of Greater omentum大網膜

THE MESENTERY: -ventral mesentery: -falciform lig. 鐮狀韌帶 -lesser omentum小網膜 -coronary lig. 冠狀韌帶 -triangular lig. 三角韌帶 -dorsal mesentery: -Mesogastrium : greater omentum大網膜, omentum bursa網膜囊 -Mesoduodenum十二指膜系膜 -mesentery proper (distal duodenum, jejunum and ileum), -mesocolon 結腸系膜 -Mesorectum直腸系膜

4 weeks 5 weeks Development of liver: -Hepatic diverticulum肝憩室 -Hepatic cords 肝索 -Gallbladder膽囊 -Ventral pancreatic bud腹側胰芽 5 weeks 6 weeks

Development of pancrease -Dorsal pancreatic bud背側胰芽 -Body and tail of pancrease, accessory pancreatic duct -Ventral pancreatic bud腹側胰芽 -Uncinate process of pancrase, main pancreatic duct

Clinical problems Annular pancrease環狀胰臟

Duodenal stenosis or atresia十二指腸栓塞或狹窄

Development of spleen Accessory spleen副脾

GI system: -Primitive Gut Morphogenesis -Foregut Embryology -Midgut embryology -Rotation of midgut loop -Retum of midgut to abdomen -Fixation of intestine -Cecum and appendix -Hindgut embryology

6 weeks Rotation of midgut loop - Counterclock wise 90 10 weeks Retum of midgut to abdomen 11 weeks

Midgut development of animals

Clinical problems Umbilical hernia ↑ ↓ Gastroschisis Muscles of abdominal wall : normal

Nonrotation of midgut Mixed rotation and volvulus Internal hernia Reversed rotation Midgut volvulus

Fixation of intestine

Cecum and appendix

Clinical problems Meckel’s diverticulum梅爾氏憩室

Ileal diverticulum迴腸憩室

Duplication of intestine腸重覆

GI system: -Primitive Gut Morphogenesis -Foregut Embryology -Midgut embryology -Hindgut embryology -Partitioning of cloaca泄殖腔 -Urorectal septum泌尿直腸隔 -Cloaca泄殖腔 -Urogenital sinus泌尿生殖竇 -Anal canal肛管

Partition of cloaca

Anal canal 恥狀線原肛

Clinical problems Type II 肛門會陰瘻管直腸陰道瘻管 Type III 直腸尿道瘻管 Type IV

Membranous atresia of anal Rectovaginal fistula 直腸陰道瘻管 Rectourethral fistula 直腸尿道瘻管