Goal 2: Development Of GI Flashcards
What arch and parts form the anterior 2/3rds of the tongue?
- 2 Lateral lingual swelling and tuberculum impar (a medial swelling)
- Arch 1
What arches and parts form the 1/3 posterior part of the tongue?
- 2,3, and anterior part of the 4th arch
- medial swelling called copula or hypobranchial eminence
What are the general sensory nerve supplies of parts of the tongue? What is different in the taste nerve supply?
GENERAL
- anterior: V3
- posterior: 9
- epiglottis: 10
TASTE
-all same except anterior: 7
What is Ankyloglossia?
- Tongue tied
- frenulum attached to tip of tongue so it’s stuck to floor of the mouth
- poor feeding with infant
Developmental path to gastrulation starting at primitive streak? What week does this happen?
Primitive steak—->epiblast—-> 3 germ layers
-week 3
Where are the walls of the digestive and respiratory tract derive from?
Splanchnic mesoderm
Where do the epithelial lining of the digestive tract derive from?
Endoderm
Where are somites derived from?
Paraxial mesoderm
What supplies the muscles of the tongue? Where are they derived from?
- CN 12, hypoglossal nerve
- myoblasts originating in occipital somites
Which germ layer undergoes neurulation? What does it form?
- ectoderm
- neural plate—> neural tube to make brain and spinal cord
What is the appearance of “Tube on top of a tube?” What forms these tubes?
- ectoderm: neural tube
- endoderm: gut tube
What type of foldings happen during week 3-4 of IUL? Where are the foldings not complete at?
- craino caudal folding with neural tube
- lateral folding, then ventral folding
- area that doesn’t fully close, but is normal, is the umbilical region where the connecting stalk and yolk sac duct remain attached
What is Gastroschisis? What causes it? How can it be detected? What other symptoms do you see with it?
- failure of lateral walls to close
- intestinal loops herniate directly into amniotic cavity so prone to abrasions from the fluid, usually lie on right side
- AFP high when abdominal organs are out so will see high AFP in mom’s blood test and amniotic fluid test
- polyhydraminos and NOT ASSOCIATED WITH CHROMOSOMAL ABNORMALITIES
What are three types of ventral wall defects?
- Ectopia Cordis: heart outside body
- Gastrochisis: intestines outside body
- Cloacal Exstrophy: urogenital organs outside body
What are the 3 divisions of the primitive gut? Where do they start and end?
- foregut: respiratory diverticulum to liver outgrowth
- mid guy: liver outgrowth to right 2/3rd and left 1/3rd of transverse colon
- hind gut: left 1/3 of transverse colon to cloacal membrane
Derivatives of Foregut? Artery? Parasympathetic and Sympathetic innervation? Where is the pain referred to?
- esophagus, stomach, duodenum(1st and upper 1/2 of second part), liver, pancreas, biliary apparatus, gall bladder
- celiac trunk
- para: vagus
- symp: pre-T5-T9 thoracic splanchnic nerves, post-celiac ganglion
- epigastrium
Derivatives of Midgut? Artery? Parasympathetic and Sympathetic innervation? Where is the pain referred to?
- duodenum(lower 1/2), jejunum, ileum, cecum, appendix, ascending colon, transverse colon (proximal/right 2/3rd)
- superior mesenteric artery
- para: vagus
- sym: pre- T10-T11 thoracic splanchnic nerves, post-s superior mesenteric ganglion
- umbilical pain
Derivatives of Hindgut? Artery? Parasympathetic and Sympathetic innervation? Where is the pain referred to?
- transverse colon (distal/ left 1/3rd), descending colon, sigmoid colon, rectum, anal canal (above pectinate line)
- inferior mesenteric artery
- para: pelvic splanchnic
- sym: pre- L1-L2 lumbar splanchnic nerves, post-inferior cell bodies
- hypogastric pain
What are the parts of the ventral mesentery?
- lesser omentum (hepatoduodenal and hepatogastric ligaments)
- falciform lig
- coronary lig
- triangular lig
What are the parts of the dorsal mesentery?
- greater Omentum (gastrorenal, gastrosplenic, gastrocolic, splenorenal lig)
- mesentery of small intestine
- mesoappendix
- transverse mesocolon
- sigmoid mesocolon
What are the intraperitoneal organs?
- organs suspended by mesentery
- stomach, liver and gallbladder, duodenum, small intestine (jejunum and ileum), tail of pancreas, spleen, cecum, appendix, transverse and sigmoid colon
What are the primary retroperitoneal organs?
- organs located behind peritoneum
- kidneys and adrenal glands, ureters, aorta, IVC, sympathetic trunks, lower rectum and anal canal
What are the secondary retroperitoneal organs?
- layers that used to be intraperitoneal until they lost a layer of mesentery during development
- pancreas (except tail), duodenum (2,3,4th part), ascending colon, descending colon, upper rectum
When does the respiratory/trachea-bronchial diverticulum (lung bud) appear in the foregut? What two structures does it separate?
- week 4 of IUL
- separates esophagus (foregut) from respiratory primordium (lung bud) by the TRACHEOESOPHAGEAL SEPTUM
What causes the esophagus to length during development? What can happen if this process doesn’t happen?
- The decent of the heart and lungs
- hiatal hernia
Where is the muscular coat of the esophagus derived from?
Splanchnic mesenchyme
What is Esophageal Atresia/Trachea-Esophageal Fistula? What causes it? Other symptoms seen?
- common: proximal esophagus ends blindly and distal esophagus connects to trachea
- caused by spontaneous posterior deviation of tracheo esophageal septum
- polyhydraminos, esophageal stenosis, projectile vomiting, hungry all the time, hard to breath, blue skin during feeding, coughing and choking while feeding
When does the stomach appear as a fulsiform dilation? What direction does it rotate? What forms the curvatures?
- 4th week
- 90 degrees clockwise
- original posterior wall grows faster than anterior wall to form the two curvatures
What is the space behind the stomach? What is a function of it?
- Omental bursa
- allows room for stomach expansion when it’s filled
What is pyloric stenosis? What can cause it? What symptoms will you see?
- extreme narrowing of pyloric lumen because of hypertrophy of circular muscle there
- erythromycin that’s given when babies are born to prevent blindness
- severe projectile vomiting especially after feeding, dehydration, always hungry, no urine output
Where does the spleen develop from? What ligaments are connected to it?
- From mesoderm within the dorsal embryonic mesentery
- gastrosplenic and splenorenal
When does the liver, gallbladder, and extrahepatic ducts develop?
Week 3
What is the difference between extrahepatic biliary atresia and intrahepatic biliary atresia?
- extra: correctable, outside liver
- intra: fetal infection cause it and is lethal, inside liver, need a liver transplant
What do the two pancreatic buds form?
- ventral: uncinate process, inferior part of head of pancreas
- dorsal: rest of pancreas
How is the pancreas formed? What forms the main pancreatic duct? Where does the accessory pancreatic duct come from?
- duodenum posteriorly rotates ventral bud around and fuse it with dorsal bud at the 2nd PART OF THE DUODENUM
- main: dorsal and ventral duct joins with bile duct and opens to major duodenal papilla
- accessory: from dorsal duct, opens to minor duodenal papilla
What is Annular Pancreas? What symptoms do you see? What disorder is it associated with?
- ventral bud roared around both sides of duodenum and forms a collar around it, choking it, see after birth
- polyhydraminos, BILE STAINED PROJECTILE VOMITING
- a/w Down’s syndrome
What primitive gut divisions does the duodenum develop from? What artery or arteries supply it? Where is the junction of the two parts? When is the duodenum recananlized and obliterated?
- foregut and midgut
- superior mesenteric and celiac trunk
- at the major duodenal papilla (opening of hepatopancreatic duct)
- at 2 months
What week does the rest of the small intestine and large intestine develop? What are the two limbs and what develops from them?
- week 5
- cephalic limb: distal part of duodenum, jejunum, part of ileum
- caudal limb: lower portion of ileum, cecum, appendix, ascending colon, proximal 2/3 of transverse colon
What are the two stages of primitive gut rotation and the week it happens? What’s happening in both stages? What artery are they wrapping around?
- week 6: 90 degree rotation where it HERNIATES through umbilical ring- PHYSIOLOGICAL UMBILICAL HERNIATION
- week 10: herniated loops rotate 180 degrees and RETRACT back into abdomen
- total is 270 degrees counterclockwise and they are rotating around the superior mesenteric artery
What is Omphalocele? What development process failed to happen? How is it diagnosed?
- herniation of abdominal viscera through enlarged umbilical ring, covered by amnion so NOT DIRECTLY STICK OUT INTO THE AMNIOTIC CAVITY
- will see from 6-10weeks since this is when the loops were supposed to retract back into the abdomen
- diagnose by Ultrasonography (USG)
- have chromosomal abnormalities
What is Meckel’s diverticulum?
- persistence of remnants of Vitelline duct
- usually asymptomatic
- might cause ulceration, bleeding or perforation
What is Vitelline fistula?
- persistence of patent Vitelline duct
- there’s DIRECT communication between umbilicus and intestinal tract
- may see fecal matter at umbilicus
What is the Vitelline duct (Omphaloenteric duct)?
- Temporary yolk sac (ileum) connection to the midgut (belly button area)
- supposed to go away naturally
- if yolk sac FAILS TO REGRESS, can lead problems
What is Vitelline Cyst?
Remnants of the duct make a cord around a large cyst that’s formed
What is Volvulus? What is Mobile Cecum? What is Retro colic hernia?
- volvulus: malrotation of gut, can get decrease bloood supply to gut and get ischemic, causes bowel abd nausea vomiting and abd pain
- mobile cecum: portion of mesocolon persistence
- retro: portion of small intestines trapped behind mesocolon
What is Hirshsprung Disease? What gene is mutated? What areas are commonly affected? What will you see in a patient with this?
- absence of parasympathetic ganglion in bowel wall (derived from neural crest)
- RET gene
- rectum more often, also sigmoid colon
- no peristalsis, no bowel movement when born, explosive forceful stool when rectal examination done
What is the process of recanalization of the gut?
- week 5: endoderm proliferates and occluded
- week 6: over 2 weeks, tube is open and hollow (recanalization-Hollow, solid, Hollow process)
- end of week 8: endoderm tube is a closed tube again
If the gut fails to recanalate, what can happen?
- stenosis: partial obstruction
- atresia: complete obstruction
What type of atresia do you see a double bubble sign on scans?
-duodenal atresia
What is an Apple Peel Atresia?
- where the jejunum ends blindly and the remaining distal bowel wraps around the blood supply there
- aka Christmas Tree Atresia
What gene problems can cause gut atresia?
HOX and FGF
