DIT review - GI 1 Flashcards
What are the neres that innervate each of the branchial arches
1st arch - CN V
2nd arch - CN VII
3rd arch - CN IX
4th-6th arches - CN X
Describe the branchial origin, as well as nerves responsible for taste, sensation, and motor of anterior 2/3 of tongue
- Anterior 2/3:
- Origin - 1st and 2nd branchial arch
- Taste - CN VII
- Sensation - CN V3
- Motor - CN XII
Describe the branchial origin, as well as nerves responsible for taste, sensation, and motor of posterior 1/3 of tongue
- Posterior 1/3:
- Origin - 3rd and 4th branchial arch
- Taste - CN IX, CN X (very posterior)
- Sensation - CN IX, CN X (very posterior)
- Motor - CN XII
Most common location of salivary gland tumors
Parotid gland
Usually benign; if they are located in a smaller gland, more likely to be malignant
Compare and contrast gastrischisis to omphalocele
- Gastroschisis
- Defect in abd wall
- Extruding viscera not covered by sac
- Other anomalies less common
- Omphalocele
- Defect in abd wall
- Extruding viscera covered by sac (composed of peritoneum and amnion)
- Liver often found protruding
- Other anomalies common
Describe the defect and presentation of tracheoesophageal fistula
- Most common type is esophageal atresia with distal tracheoesophageal fistula
- Aka blind upper esophagus with lower esophagus joined to trachea
- Presentation:
- Polyhydramnios in utero
- Air in stomach (visible on X-ray) – due to fistula
What are the components of CREST syndrome
Seen in limited type scleroderma
· Calcinosis / anti-centromere antibody
· Raynoud
· Esophageal dysmotility
· Sclerodactyly (tightening of skin with loss of wrinkles)
· Telangiectasias
What is the metaplastic change associated with Barret esophagus
Nonkeratinized stratified squamous –> columnar
What is Boerhaave syndrome
- Transmural, usually distal esophageal rupture
- Due to violent retching
- Surgical emergency
Causes of esophagitis
- GERD
- Candida (white pseudomembrane)
- CMV (linear ulcers)
- HSV (punched-out ulcers)
Triad of Plummer-Vinson Syndrome
- Dysphagia (due to Esophageal web)
- Iron deficiency anemia
- Glossitis
What is the most common esophageal cancer in America and what are its associations?
- Adenocarcinoma
- Occurs in distal 1/3 of esophagus
- Associated with chronic GERD, Barrett esophagus, obesity, achalasia
- More common in America
What is the most common esophageal cancer worldwide and what are its associations?
- Squamous cell carcinoma
- Occurs in the proximal 2/3 of esophagus
- Associated with alcohol, smoking, and hot liquids
- More common worldwide
Describe the branches of the celiac trunk
- Celiac trunk - Pharynx, esophagus, proximal duodenum, liver, gallbladder, pancreas, spleen
- Common hepatic artery
- Gastroduodenal artery
- R gastroepiploic - greater curvature of stomach (anastomoses with L gastroepiploic)
- Anterior superior pancreaticoduodenal à head of pancreas, proximal duodenum
- Right gastric artery - lesser curvature of stomach (anastomoses with L gastric a.)
- Proper hepatic artery
- Gastroduodenal artery
- Splenic artery - spleen
- Left gastroepiploic artery - greater curvature of stomach
- Left gastric artery - lesser curvature of stomach
- Common hepatic artery
What is the purpose of gastrin, and how does it accomplish this?
- G-cells
- Located in the antrum of the stomach (lower stomach)
- Produce gastrin in response to decreased HCl
- Gastrin can directly stimulate parietal cells to make gastric acid, but . . .
- Gastrin’s main mechanism of action is to increase acid secretion mostly via effect on ECL cells –> histamine release –> histamine activation of parietal cells
- Gastrin release stimulation by:
- Phenylalanine
- Tryptophan
- Calcium
What is Zollinger-Ellison syndrome
- Gastrin-secreting tumor (gastrinoma) of pancreas or duodenum
- Too much gastrin à too much gastric acid à recurrent duodenal ulcers
- Diagnosis:
- Positive secretin stimulation test
- Gastrin levels remain elevated even after administration of secretin, which normally inhibits gastrin release
- Positive secretin stimulation test
What is duodenal atresia and how does it present?
- Failure of the duodenum to recanalize, so it is basically a blind pouch
- Presents as bilious vomiting and abdominal distension
- X-ray will should “double bubble”
- Buildup of air distal to the pyloric sphincter (within the blind pouch)
- Buildup of air proximal to the pyloric sphincter within the stomach
What is the characteristic histology of abetalipoproteinemia
Acanthocytes (“spur cells”)
Pathogenesis and histology of celiac disease
- Autoimmune tolerance to gliadin (gluten protein found in wheat)
- Wheat protein cross-reacts with small bowel tissue leading to:
- Inflammation
- Antibodies against gliadin and tissue transglutaminase
- Histology:
- Blunting of villi
- Crypt hyperplasia
- Intraepithelial lymphocytosis
Describe Whipple disease (cause, presentation, histology)
- Infection with Tropheryma whipplei
- Symptoms:
- Weight loss, lymphadenopathy, hyperpigmentation, cardiac symptoms, arthralgias, neurologic symptoms
- Histology:
- PAS (+) foamy macrophages in intestinal lamina propria
What is the characteristic histology of abetalipoproteinemia
- Will see abnormal star-shaped RBCs called acanthocytes (spur cells) - irregular spikes (vs. Echinocytes/burr cells)
- Lack of apoprotein B
- B48 needed for chylomicron secretion from the intestinal cells
- Enterocytes fill with chylomicrons that cannot pass into circulation
- Fat malabsorption, steatorrhea, failure to thrive
- B100 needed for LDL reuptake in the liver
- B48 needed for chylomicron secretion from the intestinal cells
