Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Tube development • primitive gut – in 4th week folding of embryo cause partial incorporation of yolk sac into the embryo GIT development – foregut – buccopharyngeal membrane, lung bud, ventral and dorsal mesentery – midgut – from liver bud, communication with yolk sac → vitelline duct (ductus omphalomesentericus), only dorsal mesentery – hindgut – cloacal membrane, ventral and dorsal mesentery Tube rotations Pancreas development Liver development Stomach • tilting of stomach – around an axis located in the midpoint of lesser curvature → forming of duodenal loop Before intestinal rotation • gut is too long, loop formation • two loops – duodenal loop – foregut and midgut • rotation of stomach • apex – liver bud, two pancreatid buds – 90° CW around its longitudinal axis – umbilical loop – midgut and hindgut • left → anterior, right → dorsal • apex – ductus omphalomesentericus – also on distal part of esophagus • fusing of duodenal loop with dorsal wall Duodenal loop • during stomach rotation touch the dorsal wall and fuse with it • → duodenum and pancreas are secondary retroperitoneal organs Umbilical loop • • • • axis – superior mesentery art. is outside of body – physiological hernia 180° CCW around the axis outside next 90° CCW during reposition 1 Definitive position • caecum grows caudally and form colon ascendens Anomalies and malformations • pylorostenosis – hypertrophy of sphincter • omphalocoele – disorder of reposition • covered only by amnion • inborn umbilical hernia • reposition OK, later herniated • covered at least by peritoneum and amnion • malrotation – incomplete rotation – reverse rotation Hindgut • cloaca division Pancreas development • 4th week • caudal part of foregut • 2 pancreatic buds (11): – dorsal (bigger) – ventral • stenosis and atresias • anal imperforations × rectal atresias • ductus vitellinus can persist as – diverticulum Meckeli 2 Pancreas development – dorsal bud (7) grows to dorsal mesentery – ventral bud (5) to ventral mesentery – forms future uncinate process and part of caput pancreatis – migration of ventral pancreas cause fusing of buds Pancreas development • insulin secretion starts in about 10th week • abnormalities of pancreas – annular pancreas • surrounds the duodenal wall, duodenal stenosis Liver development – caudal part of foregut → liver bud (4th week) – grows to ventral mesentery Liver development • liver bud division – 1) cranial bud (larger) • future liver • bud grows through veins leading to heart to septum transversum – 2) caudal part • origin of gallbladder • forming of ductus cysticus Liver development – endodermal cells – hepatocytes – septum transversum – hematopoetic cells, Kupffer cells – umbilical and vitelline veins – sinusoids Liver development – hematopoesis since 6th week – last 2 month of intrauterine development abates – ventral mesogastrium: • mesohepaticum → lig. falciforme hepatis • omentum minus – liver covered by peritoneum, only area nuda is free 3