Embryology Flashcards
Blood supply for the foregut comes from which branch of the abdominal aorta
Celiac trunk
Branch of abdominal aorta that supplies lower duodenum, jejunum, legumes, cecum, appendix, ascending colon and proximal 2/3 of transverse colon
superior mesenteric a
Artery supplying the hindgut
Inferior mesenteric a
Mucosal epithelium and GI glands of the GI tract are derived from what germ layer (with exception of lower 1/3 of anus)
Endoderm
Muscular wall, vascular elements and CT elements of the GI tract originate from what germ layer
Splanchnics mesoderm
Enteric ganglia and nerves and Glia (NCC) and epithelium of lower 1/3 of anus are derived from what germ layer
Ectoderm
Adult derivatives of the dorsal mesentery
Greater momentum (gastrosplenic, gastronomic, splenorenal ligaments) SI mesentery Mesoappendix Transverse mesocolon Sigmoid mesocolon
Adult derivatives of the ventral mesentery
Lesser momentum (hepatoduodenal and hepatogastric ligaments)
Falciform ligament of liver
Coronary ligament of liver
Triangular ligament of liver
The esophagus, stomach, liver, gallbladder, pancreas and upper duodenum are derived from what embryonic structure
Foregut
During GI development, the stomach rotates 90 degrees ____, putting the dorsal mesentery to the R/L and the ventral mesentery to the R/L
CCW
Ventral moves right
Dorsal moves left
Lesser sac ends up behind stomach, dorsal mesogastriu enlarges forming greater momentum
The left vagus nerve is associated with which mesogastrium
Ventral
The right vagus nerve is asssociated with which mesogastrium
Dorsal
Narrowing of the pyloric lumen obstructing food passage is known as
Hypertrophic pyloric stenosis
Hypertrophic pyloric stenosis is caused by a failure of which cell type (and germ layer) to proliferate, causing a decrease in ______ (cell population)
NCC, Ectoderm
Decrease in ganglion cells of enteric nervous system
The liver begins as a Diverticulum of the gut endoderm t/f
T
Endodermal derivatives of the liver
Hepatocytes, bile ducts, hepatic cells
Splanchnic mesoderm derivatives of the liver
Stromal cells, kupffer, stellate cells
The pancreas is an entirely ______ (germ layer) based organ
Endoderm
What is the fate of the ventral pancreatic duct during development
Migrates and joins dorsal pancreatic duct that is growing into the dorsal mesentery
The dorsal pancreas makes up which parts of the pancreas?
The ventral pancreas makes up which parts of the pancreas?
Dorsal - tail, body, head
Ventral - uncinate process
Pancreatic abnormalities can include
Accessory pancreatic duct
Pancreas divisum - unconnected ventral and dorsal ducts
Annular pancreas - pancreas wraps duodenum and strangulates it
If the ventral pancreas migrates around both sides of the duodenum, it is possible for it to be unable to reach its final destination by the dorsal pancreatic bud and cause what pathology
Annular Pancreas
Duodenal obstruction or stenosis
Bilious vomiting (if inferior to bile duct)
Low birth weight
Bile is first formed by ______ cells during week ____
Hepatic cells
Week 12
During gallbladder development, the duct lien is first closed but opens during what process
Recanalization
Progressive neonatal jaundice with onset after birth White clay stool Dark urine 12-19 month survival time Treatable with liver transplant
Biliary atresia
Biliary atresia is caused by an obliteration of what
Extrahepatic and/or intrahepatic ducts
Ducts replaced by fibrotic tissues due to acute or chronic inflammation
The spleen forms during what week of embryonic development
What germ layer is it derived from
5
Mesoderm
Lower duodenum, jejunum, ileum, cecum, appendix, ascending colon, proximal 2/3 of transverse colon are all structures of the
Midgut
Due to limited size of the abdomen, the lengthening midgut must herniate through the _____
(Out at 6, back by 10)
Umbilicus
The first gut rotation of ____ degrees ___ occurs at what day of fetal development and brings the cecum and future ascending colon into the left side
90 degrees CCW
50 days
The second gut rotation of ____ degrees __ occurs at __ days and brings the cecum to the ULQ and ascending colon anterior to duodenum
180 CCW
70 days
When the midgut returns to the cavity, the cecum descending into the lower right quadrant carrying the _______ along with it to the right side
Ascending colon
Retroperitoneal viscera
Thoracic esophagus
Rectum
Secondarily retroperitoneal viscera
Pancreas, duodenum, ascending and descending colon
Intraperitoneal viscera
Liver, abdominal esophagus, stomach, transverse colon, cecum, ileum, jejunum, sigmoid colon
Herniation through the umbilicus with a peritoneal covering is known as a
Omphalocele
Hernation of the bowels through the abdominal wall wth no peritoneal covering is known as
Gastroschiscis
2% incidence 2x more common in males 2% have medical symptoms 2 feet proximal to terminal ileum 2 inches long 2 years of age Leads to abdominal swelling, intestinal obstruction, bowel sepsis, and GI bleeding
Meckel’s Diverticulum
A failure of the yolk stalk connection to the midgut to regress
Non-rotation of the midgut loop
Completes first 90 degree CCW rotation but does not complete remaining 180 degree CCW rotation, resulting in
Left side colon and right sided small intestine
Reverse gut rotation
Completes initial 90 CCW but does 180 CW
Transverse colon ends up posterior to duodenum
Rolled up, twisted intestines with acute abdominal pain, vomiting and GI bleeds is known as a
Volvulus
the lumen of the intestines is temporarily obliterated because of endodermal proliferation during what month of fetal development
4-5th month
As a result of failure of endodermal degeneration to reopen lumen of intestines, what two pathologies can occur?
Duodenal stenosis - partial occlusion due to ineffective recanalization
Duodenal atresia - complete occlusion of lumen
Associated with trisomy 21
Distal 1/3 of transverse colon, descending colon, sigmoid colon, rectum, and superior 2/3 of anal canal are all __________ derivatives
Hindgut
What structures partitions the cloaca into dorsal anorectal and ventral urogenital sinus
Urorectal septum
Before the urorectal septum reaches the perineum, what occurs to the cloacal membrane
Ruptures, opening both the UG sinus and anal canal to the exterior
Vasculature of rectum, inferior mesenteric a, reveals its germ layer origins of
Endoderm
Vascular supply of the anus by the internal iliac a reveals its germ layer origin:
Ectoderm
The _________ divides the superior 2/3 and inferior 1/3 of the anus, demarcating the neurovascular supply to each region
Pectinate line
If the anal membrane fails to rupture, what can occur
Imperforated anus Low Intermediate High Atresia
Defects in the urorectal septum will usually result in what substance being found in the vagina or urine of males
Meconium
Absence of the ganglionic plexus due to absence of migration of NCC cells, causing hypertrophy of preceding regions of the bowel is known as
Hirschsprung’s disease
Hypertrophic pyloric stenosis has been associated with infants who have been treated with what antibiotic
Results in what type of vomitus
Erythromycin
Non-bilious
Pancreatic islets consist of alpha, beta, and delta cells, which secrete glucagon, insulin, and somatostatin, respectively. These cells are derived from what germ layer?
Endoderm
A 2 month old baby with sever jaundice also has dark colored urine (deep yellow) and white clay colored stool. Which fo the following disorders might be suspected
Extrahepatic biliar atrasia
A 28 day old baby is brought to the physician because of projective vomiting after feeding. Until this time, the baby has had no problems feeding. ON examination, a small knot is palpate at the right costal margin. Which of the following disorders might be suspected?
Hypertrophic Pyloric stenosis
Which artery supplies foregut derivatives of the digestive system?
Celiac trunk
The most common type of anorectal malformation is
Anorectal agenesis
The simple columnar or cuboidal epithelium lining the extrahepatic biliary duct is derived from
Endoderm
A 4 day old baby boy has not defecated since coming home from the hospital even though feeding has been normal without any excessive vomiting. Rectal examination reveals a normal anus, anal canal, and rectum. However, a large fecal mass is found in the colon, and a large release of flats and feces follows the rectal exam. What condition is suspected?
Colonic aganglionosis
Which of the following structures is derived from the midgut Appendix Stomach Liver Pancreas Sigmoid colon
Appendix
A 3 month old baby girl presents with a swollen umbilicus that has failed to heal normally. The umbilicus drains secretion and there is a passage of fecal matterial through the umbilicus ast ties. What is the most likely diagnosis
Ileal diverticulum
The midgut loop normally herniates through the primitive umbilical ring into the extraembryonic coelom during week 6 of development. Failure of intestinal loops to return to the abdominal cavity by week 11 results in
Omphalocele
Kupffer Cells present in the adult liver are derived from
Mesoderm
The simple columnar and stratified columnar epithelia lining the lower part of the anal canal is derived from
Ectoderm
A baby born to a young woman whose pregnancy was complicated by polyhydramnios was placed in the ICU because of repeated vomiting containing bile. The stomach was markedly distended and only small amounts of meconium had passed through the anus. What is the most likely diagnosis
Duodenal atresia
