Embryology (Gastrointestinal Development) Flashcards
Gastrointestinal Development of Foregut (6)
- esophagus
- stomach
- proximal duodenum
- pancreas
- liver
- biliary system
Gastrointestinal Development of Midgut (6)
- distal duodenum
- most small intestine
- cecum
- vermiform appendix
- ascending colon
- proximal ½ transverse colon
Gastrointestinal Development of Hindgut (5)
- distal ½ transverse colon
- descending colon
- sigmoid colon
- rectum
- superior part of anal canal
Esophagus Development
The tracheo-esophageal folds invaginate
Innervation of Stomach
Dorsal stomach wall (greater curvature) - right vagus
Ventral stomach wall (lesser curvature) - left vagus
Greater Omentum Development
It moves anterior to transverse colon then fuses with it
Pancreas Development
Dorsal & ventral pancreatic buds grow between dorsal & ventral mesentary then fuse
Billary Development
- Cranial portion froms liver
- Caudal portion forms gallbladder & cystic duct
Urorectal Septum
dives between two divisions of cloaca to form separate outlets for urogenital & digestive systems
Lower Anal Canal Development
- Develops from proctodeum
- NOT a hindgut derivative
Pyloric Stenosis
- Thickening of the smooth muscle in the pyloric region of the stomach
- Narrow canal prevents food from emptying properly from the stomach to the duodenum
Duodenal Stenosis
- Lumen is narrowed as a result of failed recanalization
- Symptoms: vomiting
- Associated with polyhydramnios due to low intestinal reabsorption of amniotic fluid
Duodenal Atresia
- Lumen is occluded as a result of failed recanalization
- Often associated with other severe congenital abnormalities
- Symptoms: vomiting shortly after birth, stomach distension and “double-bubble” sign
- Associatedwith polyhydramnios due to low intestinal reabsorption of amniotic fluid
Congenital Omphalocele
- Persistence of midgut herniation in the umbilical cord
- Herniated intestine fails to return to the abdominal cavity
- Herniated gut is enclosed by the epithelium of the umbilical cord
Umbilical Hernia
- Midgut hernia reduces normally, but herniates again through an imperfectly closed umbilicus
- Herniated bowel is covered by subcutaneous tissue and skin
Gastroschisis
- Defect in the ventral abdominal wall
- Abdominal viscera extrude through a split in the abdominal wall without umbilical cordinvolvement
- Results from incomplete embryonic folding
Ileal (Meckel’s) Diverticulum
- Persistence of the proximal yolk stalk
- May become inflamed and present like appendicitis
- Sometimes contains portions of gastric mucosa in its walls, producing ulceration and bleeding
Congenital Megacolon
- Neurological dysfunction that affects the colon
- Abnormality in autonomic ganglia causes failure of peristalsis in the aganglionicsegment
- Intestinal contents accumulate proximal to this point, enlarging the colon
Annular Pancreas
- Ventral pancreatic bud fuses with the dorsal bud both ventrally and dorsally
- Forms a ring of pancreatic tissue around the duodenum
- Clinical signs include duodenal obstruction shortly after birth.
Anorectal Agenesis
- Rectum ends too far superior
- Can end blindly
- Can make a fistual with the bladder (rectovesical fistula), urethra (rectourethral), vagina (rectovaginal), or vestibule (rectovestibular)
