GI Flashcards
What fetal GI structures develop at 3.5 weeks?
Foregut and hindgut
Liver bud
What fetal GI structures develop at 4 weeks?
Esophagus and stomach separate (foregut)
Intestine (single tube)
Hepatobiliary system (foregut)
Pancreas (midgut)
What fetal GI structures develop at 5-9 weeks?
Mouth, esophagus, stomach move to normal position
Intestine herniates into umbilical cord, rotation occurs
Jejunal villi form
What fetal GI structures develop at 10 weeks?
Intestines return to abdomen
Microvilli form
Crypts of Lieberkuhn develop
What fetal GI structures develop at 12 weeks?
Parietal cells (stomach) Taste buds Muscularis/muscle layers (13) Disaccharides Islet cells Bile secretion
What fetal GI structures develop at 16 weeks?
Sucking/swallowing Villi throughout intestine (14) Meconium Lipase Trypsin
What fetal GI structures develop at 18 weeks?
Ganglion cells
Crypts (19)
What fetal GI structures develop at 20-24 weeks?
Amylase (oral) Ciliated columnar cells Maltase Sucrase Pancreatic amylase (22)
What fetal GI structures develop at 28 weeks?
Disaccharidases at adult levels (30)
Lactase ^
What fetal GI structures develop at 32 weeks?
Normal gastric emptying
HCl detected in stomach
What fetal GI structures develop at 34-36 weeks?
Coordinated suck/swallow
Rapid peristalsis
Lactases at adult levels (36)
What are the enzymes that aid in carbohydrate digestion?
Pancreatic amylase Glucoamylase Intestinal disaccharidases Colonic bacteria Glucose transport Lactase
When does the fetus develop pancreatic amylase
Present at 22 weeks
Decreased secretion at birth
What is the function of glucoamylase?
Fully active at birth
Located in intestinal brush border
Removes glucose from end of starch
What are the glucosidases/disaccharidases and when do they reach normal levels?
Sucrase
Maltase
Isomaltase
28 weeks
What is the role of colonic bacteria in carbohydrate digestion?
Ferment malabsorbed carbohydrates to acids–>
colonic absorbtion
Colonic salvage pathway
Where does glucose transport occur in the GI tract?
In the small intestine
Less efficient with decreasing gestational age
Lactase reaches adult levels at
36 weeks
Chymotrypsin and trypsin are present in the
Duodenum
Decreased in preterm and term infants
Dipeptidase is present in
Mucosa
Present early in gestation
Amino acid transport capacity reaches normal levels at
Early gestation
Fat digestion occurs primarily through the action of
Bile acids
Pancreatic lipase
To compensate for decreased bile acids and pancreatic lipase at term, preterm and term infants digest fats through
Lingual lipase Gastric lipase Breast milk lipase Chylomicron formation Increased medium chain fatty acids in diet
Enzymes present in the mouth are
Salivary amylase
Lingual lipase
Enzymes present in the stomach are
Pepsinogen Acid Chyme Intrinsic factor Gastrin Gastric lipase
Pancreatic enzymes are
Pancreatic amylase Chymotrypsinogin Chymotrypsin Trypsinogen Trypsin Pancreatic lipase
Liver produces ____ for digestion
Bile
Small intestine enzymes are
Enterokinase Glucoamylase Disaccharidases (maltase, sucrase, lactase) Amino peptidases Dipeptidase Intestinal Cholecystokinin Secretin Gastrin inhibitory peptide Motilin
Large intestine contributes to digestion through the
Salvage pathway
Esophageal duplication presents as
Posterior mediastinal mass that can compress trachea and cause respiratory distress
Can also compress esophagus and cause feeding intolerance
Esophageal cysts are
Located in muscular wall and lined by ciliated, gastric, or squamous epithelium
The most common type of TEF is
Esophageal atresia with distal TEF (85%)
Most TEFs are
Isolated anomalies (30-40% with other anomalies) Rarely familial
Can be associated with VACTERL
Occurrence of pyloric stenosis is associated with
3/1,000 birth
5 to 1 males»>females
O and B blood types
Duodenal atresia is commonly associated with
Trisomy 21 Malrotation CHD Annular pancreas Esophageal atresia GU anomalies
Duodenal atresia occurs due to
Failed recannelization of intestinal tube, 8 to 10 weeks gestation
Jejunal-ileal Atresia most often occurs with _____ atresia in the _____
Single atresia
Distal ileum
Jejunal-ileal Atresia occurs due to
Ischemic injury after intestinal development
Small left colon syndrome is associated with
Maternal diabetes Maternal hypothyroidism Maternal toxemia / magnesium Prematurity Cecal perforation
Microcolon is a result of
Functional immaturity of the ganglion cells
Colonic atresia is caused by
Ischemia
Most infants with hirschsprung disease are
Male (80%) and related to an individual who also has hirschsprung disease
hirschsprung disease is associated with
Trisomy 21 Heterochromia Waardenberg syndrome Congenital deafness 13Q deletion Pheochromocytoma Neurofibromatosis Neuroblastoma
hirschsprung disease most often occurs in the
Rectosigmoid colon
Meconium plug is differentiated from meconium ileus by
Location in the colon, in contrast with meconium ileus which involves distal ileum
Meconium plug is caused by
Immaturity of myenteric plexus nerve cells in the colon
Imperforate anus associated with rocker bottom perineum usually indicates
Sacral agenesis
Pancreatic insufficiency associated with Schwachmann-Diamond syndrome includes
Bone marrow dysfunction
Short stature
Normal sweat test
Pancreatic insufficiency associated with cystic fibrosis includes
Chr 7 508 position mutation
CFTR chloride transporter abnormality
FTT vitamin k malabsorption Hypocalcemia Cholestasis Rectal prolapse Nasal polyps Peptic ulcers Pancreatitis
Pentalogy of Cantrell includes
Sternal cleft Anterior midline diaphragmatic abnormality Pericardial defect Ectopic cordis Omphalocele
All infants with gastroschisis also have
Malrotation
Omphalocele is more common in
Males (3:1)
Association with other defects/syndrome (59-89%)
Associated syndromes with omphalocele are
Trisomy 13, 18, 21
Pentalogy of Cantrell
Beckwith-Wiedeman
OEIS
Cause of omphalocele is
Intestinal loops fail to return to abdomen at 11 weeks
Somatic folds fail to complete abdominal wall at 18 weeks
The ________ distinguishes upper from lower GI bleeding
Ligament of Treitz
___% of infants <1500g will develop NEC
10%
Bloody stools and focal pneumatosis is NEC stage ____
2A
Abdominal findings including edema/ascites with portal venous gas on x-ray is NEC stage ____
2B
Diffuse systemic signs with abdominal edema/erythema and persistent bowel loops distention is NEC stage ____
3A
NEC stage 3B is marked by
Pneumoperitoneum
Prognosis for short bowel syndrome is worse if
Colon resected
Ileocecal valve removed
>25cm bowel+ ileocecal valve resected
>40cm resected without valve