Gastrointestinal Tract Flashcards
Discuss how to differentiate the jejunum and the ileum
Wall: - jejunum have thicker walls with larger diameter Location - jejunum located in left quadrant - ileum located in right lower quadrant Vascularity - jejunum have greater vascularity so appear darker - vasa recta are long in jejunum Mesenteric fat - jejunum have less mesenteric fat Circular Folds - jejunum have tightly packed circular folds Villi - jejunum have more numerous villi Lymph node - ileum have Peyer's patches
Discuss the differences in tissue above (visceral) and below (somatic) pectinate line
Embryology
- visceral is endoderm where somatic is ectoderm
Innervation
- visceral is autonomic
- somatic is pain sensation from in rectal nerve
Blood supply
- visceral is superior rectal artery and vein from IMA/V
- somatic is inferior rectal artery from internal iliac and middle/inferior rectal vein from IVC
Lymphatics
- visceral pattern
- somatic have body wall drainage
Discuss the digestion and absorption of proteins in the GI tract
Stomach
- proteins denatured by gastric acid
- pepsinogen secreted by chief cells activated by gastric acid cleave protein into peptides
Duodenum
- pancreatic proteases (trypsinm chymotrypsin) cleave peptide into oligopeptides
- brush border enzymes (-peptidase) cleave oligopeptides
Small Intestine
- absorbed by enterocytes via co-transport with Na
Blood
- leave epithelial cell by diffusion
Discuss the digestion and absorption of carbohydrates
Mouth - salivary amylase break starch - simple sugars can be absorbed by mouth Duodenum - pancreatic amylase break down starch Small Intestine - brush border enzymes break disaccharide into monosacchride Absorption - glucose and galactose absorbed with co-transport of Na
Discuss the digestion and absorption of fat
Mouth and Stomach
- mastication break down fat
- gastric lipase break down fat
Duodenum
- bile salts emulsify fat to break it down into fat droplets
- pancreatic lipase cleave triglyceride into fatty acids
- pancreatic phospholipase break phospholipids into fatty acids
- pancreatic cholesterol esterase break cholesterol into sterol
- cleaved fatty acids, monoglyceride, choline and sterol form micelle with bile salt
Small Intestine
- micelle diffuse into enterocyte where can reform triglyceride to form chylomicron which can exit and enter lymphatic
List the risk factors for a hernia
- body habitus which increases intra-abdominal pressure: obesity, pregnancy, ascites
- activities which increase intra-abdominal pressure: chronic cough, constipation, straining, heavy lifting
- congenital anomaly with patent processus vaginalis
- male increased risk for indirect inguinal hernia due to opening in inguinal canal
- female increased risk for femoral hernia
Differentiate between a indirect and direct inguinal henia
Indirect
- herniation originating deep inguinal ring lateral to inferior epigastric artery that descends into scrotum or labia majora
Direct
- herniation through Hesselbach’s triangle medial to inferior epigastric artery
- Hesselbach triangle is medial= lateral margin of rectus, lateral=inferior epigastric artery, inferior=inguinal
Discuss what is a femoral hernia
- herniation into femoral canal, medial to femoral vein
- greatest risk for incarceration
Discuss the presentation and management of a hernia
Presentation
- fullness at hernia site with enlarging mass with valsava with disappearance when supine
- aching sensation in area, worse at end of day
- incarcerated have painful, non-reducible mass with symptoms of bowel obstruction
- strangulated have irreducible hernia with symptoms of bowel obstruction and fever/peritonitis
Investigation
- CT or ultrasound
Management
- usually have surgical repair within 1 month of hernia unless it is minimally symptomatic and first occurence
Discuss the presentation and management of peptic ulcer
Etiolgy - H Pylori infection - NSAID - gastric cancer Presentation - dyspepsia (gastric worse with food and duodenal improve) - hemetemesis - melena - epigastric tenderness Management - if H pylori positive then quadruple therapy of PPI, bismuth, tetracycline, metronidazole) - discontinue NSAID Surgical Indications - refratory to medical management - hemorrhage - perforation - obstruction
Discuss the presentation and management of an acute surgical abdomen
Presentation - acute, severe abdominal pain - unstable vital signs - peritonitis: guarding, rigidity, rebound tenderness, tenderness to percussion Investigations - routine bloodwork - AXR for possible perforation or obstruction - CT Management - stabilize - early surgical intervention
Discuss the pathophysiology of a bowel obstruction
- have disruption of the normal flow of contents leading to upstream dilatation and downstream collapse
- dilatation can interrupt blood supple leading to ischemia and bowel wall edema
- Venous congestion impairs normal bowel absorption leading to increased intra-luminal fluid and fluid loss into peritoneal cavity causing electrolyte imbalances
List the differential for a small bowel obstruction
Intraluminal - intussusception - gallsontes Intramural - Chron's - radiation stricture - adenocarcinoma Extramural - Adhesions - hernia - peritoneal carcinomatosis
Discuss the presentation and management of a small bowel obstruction
Presentation - nausea and vomiting - bloating - diffuse abdominal pain - constipation and obstipation - distended abdomen with hyper-resonance Investigations - AXR: distended small bowel loops with air fluid level - thicker wall, pliacae circularis, and located in middle abdomen and are smaller Management - NG tube decompression with bowel rest - surgery if no resolution in 2-3 days, complete obstruction
List the differential for a large bowel obstruction
Intraluminal - constipation Intramural - adenocarcinoma - diverticulitis - IBD striction - radiation stricture Extramural - volvulus - adhesions
