GI Embryology-1/12/16 Flashcards
The epithelial lining and glands are components of this dermal layer:
The lamina propria, submucosa, muscularis layers, and serosa/adventitia are components of this dermal layer:
Endoderm
Splanchnic mesoderm
The gut tube becomes suspended by a this 2-layered fold of peritoneum:
Dorsal Mesentery
Visceral peritoneum is ___ mesoderm
Parietal peritoneum is ___ mesoderm
Splanchnopleuric
Somatopleuric
List the sympathetic preganglionic cell bodies for:
a) foregut
B) midgut
C) hindgut
A) T5-T9 (Greater splanchnic n.)
B) T9-T12 (lesser splanchnic n.)
C) T12-L2 (least splanchnic n.)
List the parasympathetic preganglionic cell bodies and nerve for :
A) Foregut
B) Midgut
C) hindgut
A) Brainstem (Vagus n.)
B) Brainstem (Vagus n.)
C) S2-S4 (Pelvic splanchnic nerves)
A 2 month old comes into your clinic and upon imaging, you find that the baby has a narrowed (occluded) esophagus in the lower 1/3 of the esophagus. You believe that this was caused by some sort of vascular abnormality or compromised blood flow and diagnose this baby with:
Esophageal stenosis or atresia–> narrowed or occluded esophagus due to incomplete recanalization, usually found in the lower 1/3 of esophagus
May also be caused by vascular abnormality or compromised blood flow
Slide 23
This type of esophageal atresia requires an esophageal replacement:
Long Gap
After the rotation of the stomach, what becomes of the left vagus nerve?
Left vagus becomes the anterior vagal trunk (Right vagus becomes posterior vagal trunk)
A mother brings her 3 week in to your pediatric clinic and complains that her child has been projectile vomiting after meals. She explains that the vomit is generally the color of the food she eats and does not appear to contain bile (your assessment). You correctly diagnose the baby with:
Hypertrophic pyloric stenosis–> usually presents 2-3 weeks after birth; projectile vomiting/no bile; can have protruding rib cage and scaphoid abdomen
Slides 36-37
A duodenal stenosis typically occurs in the ____ duodenum
A duodenal atresia typically occurs in the ____ duodenum
3rd or 4th part (small lumen)
Usually 2nd or 3rd part (occluded lumen)
You are provided a front radiograph during your radiology rotation and note that the image shows a gas-distended stomach as well as a proximal duodenum with no distal gas. You tell your attending that this is a “Double Bubble” sign and confirm that this patient has:
A duodenal atresia–> occluded lumen, usually 2nd or 3rd part; 1/4 also have Down’s; Double Bubble sign
Slide 39
A ____ is a tubular structure with an internal lining with an internal lining of GI epithelium, smooth muscle in its wall and adherence to some portion of the alimentary tract
Duplication cyst
Slide 40
The liver develops in the ___ mesentery
The gallbladder and bile ducts develop in the ____ mesentery
The pancreas develops from ___ mesentery
Ventral
Ventral
Buds in both ventral and dorsal mesenteries
All foregut endoderm has the potential to express ____-specific genes and differentiate into this tissue
Liver
____ instruct the gut endoderm to express liver-specific genes
Cardiac mesoderm/septum transversum
Cardiac mesoderm secretes FGF2
The growth of the liver divides ventral mesentery into these 2 structures:
Falciform ligament
Lesser Omentum
The ____ is the fibrous remnant of the DUCTUS VENOSUS
The ____ is the obliterated LEFT UMBILICAL VEIN
Ligamentum venosum
Ligamentum teres hepatis (round ligament
Shortly after the birth, you notice that a neonate is jaundiced with incredibly dark urine and pale stool. You determine that there is an incomplete canalization of the bile duct and correctly diagnose the baby with:
Extrahepatic biliary atresia–> incomplete canalization of the bile duct; 1/15,000 live births
Jaundice- high levels of bilirubin in the blood
Dark urine- bilirubin filtered by kidney and excreted in urine
Pale stool- no bile or bilirubin is being emptied into the intestine
Tx-Surgical correction or transplant
Slide 54
This liver disorder is a decrease in the cells’ ability to absorb copper and is also known as “kinky hair” syndrome
Menkes disease
This liver disorder is characterized by copper not being eliminated properly and accumulates. A “Kayser-Fleischner” ring can be noted.
Wilson’s disease
List the transcription factors for the developmental molecular regulation of:
A) Pancreas and duodenum
B) cells secreting insulin, somatostatin, and pancreatic polypeptide
C) cells secreting glucagon
A) PDX1
B) PAX4
C) PAX6
You are viewing a CT scan that you ordered for a patient who has a duodenal obstruction. You think back to your embryology courses and remember that this particular disorder is characterized by the ventral and dorsal pancreatic buds forming a ring around the duodenum during development. This patient likely has a:
Annular pancreas (pancreatic tissue encircling the duodenum)
Slide 60
Describe the rotation of the FOREGUT:
The stomach moves to the left
The liver moves to the right
Relative size of the 2 peritoneal cavities changes
Right side is getting smaller
You are observing a section of removed small intestine from a cadaver in the anatomy lab. You find that proximal jejunum is short and the portion distal to the defect is coiled around a mesenteric remnant. Clinically, this disorder is associated with low body weight and other abnormalities. What is the disorder?
Apple peel atresia
Slide 65
When does rapid growth of the midgut generally begin?
Week 6
This disorder generally presents within the first week as duodenal obstrution with bilious vomiting. Infants may present with recurrent abdominal pain, intestinal obstruction, malabsorption/diarrhea, peritonitis/septic shock, solid food intolerance, common bile duct obstruction, abdominal distention, failure to thrive.
Intestinal malrotation
Slide 75
___ is an abnormal twisting of the intestine causing obstruction and may cause abnormal twisting of the intestine causing obstruction
Volvulus
Slide 76
This disorder is an enfolding of one segment of the intestine within another and is characterized and initially present with recurring attacks of cramping abdominal pain that gradually become more painful
Intussusception
Slide 79
A baby is born with a herniation of abdominal contents through an enlarged umbilical ring. The herniation is surrounded by a pale, shiny sac that has protruded from the base of the umbilical cord. What is the diagnosis?
Omphalocele–> Herniation of abdominal contents through enlarged umbilical ring
-Normal if it is temporary and the gut should return into the abdomen as the embryo grows
Slides 85-86
A newborn presents with herniated gut contents that are not surrounded by a membrane is diagnosed with this disorder that is a failure of anterior abdominal wall musculature to close during folding.
Gastroschisis–> Failure of anterior abdominal wall musculature to close during folding
-Gut contents NOT surrounded by membrane
Slide 96
This body wall defect has guts within the umbilical cord
This body wall defect has guts not within the umbilical cord
Omphalocele
Gastroschisis
A young male infant presents with deficient anterior abdominal wall musculature, a mega-ureter, and undescended testicles. What is the most likely diagnosis?
Prune Belly or Eagle-Barrett syndrome
Common triad of features:
1) Anterior abdominal wall: musculature is deficient or absent
2) Urinary tract anomalies (mega-ureters, large bladder)
3) Bilateral cryptorchidism (undescended testes)
- Occurs almost exclusively in males, no urethral anomalies seen in females
- Slide 99
What are 2 hypotheses for prune belly syndrome?
Urinary Tract obstruction
Primary mesodermal development defect (prevailing)
A failure of the vitelline duct to close can lead to:
Meckel’s (ileal) diverticulum–> asymptomatic, gastric or pancreatic tissue
-Remnant of vitelline duct
-Failure of VD to close
-Rule of 2’s
-Will have a fistula present and FECAL DISCHARGE through umbilicus
Slides 104-106
These cells colonize the entire foregut, midgut, cecum, and hindgut and give rise to the majority of the Enteric NS
Vagal neural crest cells
This outer enteric plexus is situated between the longitudinal and circular muscle layers
This inner enteric plexus forms later in gestation and resides in the submucosa
Myenteric (Auerbach)plexus
Meissner’s (submucosal) plexus
Hirschprung’s disease (congenital aganglionic megacolon) is a motor disorder of the colon that causes a functional intestinal obstruction in which both enteric plexuses are affected. What is the pathogenesis of this disease?
Failure of migration of neural crest cells that form the colonic ganglion cells
Without parasympathetic innervation, the colon cannot relax or undergo peristalsis, resulting in a functional obstruction
Slide111
____ is any organ that developed outside the abdominal cavity (kidney) which never had a mesentery to begin with
____ are portions of the gut tube whose mesentery has fused with the lining peritoneum
_____ are organs with a mesentery
Primarily retroperitoneal
Secondarily retroperitoneal
Intraperitoneal
List intraperitoneal viscera
Stomach Gallbladder and bile duct Jejunum and ileum Appendix Cecum Transverse colon Sigmoid colon
List retroperitoneal viscera
Thoracic esophagus
Rectum
List secondarily retroperitoneal viscera
Duodenum (parts)
Pancreas
Ascending and descending colon
The cloaca develops from ____
Hindgut endoderm
The cloaca is divided by the urorectal septum into ____
Urogenital sinus
Rectum
____ is a malformation of the anorectal region that may occur in several forms.
Imperforate anus
____=If the anal canal ends as a blind sac below the pelvic diaphragm
____=If the rectum ends as a blind pouch above the pelvic diaphragm
Anal agenesis
Anorectal agenesis (most common)
A newborn fails to pass her first stool within 2 days and appears to not have an anal opening. She eventually passes a stool by way of the vagina. What does she have?
Imperforate anus
Slide 127
Regarding molecular regulation of gut tube development, specification is initiated by the ____ gradient that causes transcription factors to be expressed in different regions of the tube.
It also requires interaction between epithelium (endoderm) and mesenchyme (splanchnic mesoderm) initiate by ___
Retinoic acid
SHH
