Embryology Of The Gastrointestinal System Flashcards
What part of the gut tube is encoded by SOX2?
Esophagus
What part of the gut tube is encoded by PDX1?
Duodenum and pancreas
What part of the gut tube is encoded by CDXC?
Small intestine
What part of the gut tube is encoded by CDXA?
Large intestine
Specificiation in the gut tube is initiated by an RA gradient that causes transcription factors to be expressed in different regions of the tube. What is also required in the gut tube?
An interaction between the epithelium (endoderm) and mesenchyme (splanchnic mesoderm) initiated by SHH.
In addition to regionalization, development of the gut tube also involves:
Continuous elongation
Herniation past the body wall (into the umbilical cord)
Rotation and folding for efficient packing
Histiogenesis and further maturation of the epithelial lining.
What is the 2 layered fold of peritoneum that the gut tube becomes suspended by?
Dorsal mesenteries
What are mesenteries?
Reflections of parietal peritoneum onto the gut tube.
How many segments is the gut tube divided into?
3.
Foregut, midgut and hindgut.
Innervation and blood suplpy to these segments is strongly patterned.
What organs are found in the foregut?
Esophagus
Stomach and 1/2 duodenum
Liver
Gall bladder
Pancreas
Spleen
What organs are found in the midgut?
1/2 duodenum
Jejunum
Ileum
Cecum and appendix
Ascending colon
2/3 transverse colon
What organs are found in the hindgut?
1/3 transverse colon
Descending colon
Sigmoid colon
Rectum
Upper part of the anal canal
What artery supplies the foregut?
Celiac artery
What vessel supplies the midgut?
Superior mesenteric artery
What artery supplies the hindgut?
Inferior mesenteric artery.
What preganglionic cell bodies (and nerve) supply the foregut?
T5 - T9
Greater splanchnic nerve
What preganglionic cell bodies (and nerve) supply the midgut?
T9 - T12
Lesser splanchnic nerve
What preganglionic cell bodies (and nerve) supply the hindgut?
T12 - L2
Least splanchnic nerve
The least splanchnic nerve goes to what plexus?
Aortico-renal plexus
What plexus do the lumbar splanchnics from L1 and L2 go to?
Inferior mesenteric plexus
What is the parasympathetic innervation of the forgut and midgut?
Vagus nerve
What is the parasympathetic innervation of the hindgut?
Pelvic splanchnic nerve
What are preganglionic cell bodies found in the foregut and midgut?
Brainstem
Where are preganglionic cell bodies of the hindgut found?
S2 - S4