Back to AI Flashcard MakerAnatomy and Physiology /USMLE - GI Flashcards Part 6
USMLE - GI Flashcards Part 6
This deck covers key concepts related to gastrointestinal physiology and pathology, focusing on digestion, absorption, and related disorders.
Salivary Amylase Role MoA Yields
Starts digestion | Hydrolyzes α(1-4) linkages to yield disaccharides (maltose and α-limited dextrins)
Tap or swipe ↕ to flip
Swipe ←→Navigate
1/25
Key Terms
Term
Definition
Salivary Amylase Role MoA Yields
Starts digestion | Hydrolyzes α(1-4) linkages to yield disaccharides (maltose and α-limited dextrins)
Pancreatic Amylase Concentrated in MoA
Highest concentration in duodenal lumen | Hydrolyzes starch to oligosaccharides and disaccharides
Oligosaccharide Hydrolase Location Role MoA
At brush border of intestines Rate limiting step in carbohydrate digestion Produces monosaccharides from oligo- and disaccharides
Carbohydrate absorption What kind of carbs? By what cells? What enzymes remove them from lumen? What enzymes transport them to the blood?
Only monosaccharides (glucose, galactose, and fructose are absorbed by enterocytes Glucose and Galactose are taken up by SGLT1 (Na dependent) Frucose ...
How to distinguish GI mucosal damage from other causes of malabsorption?
D-xylose absorption test
Iron absorption Ionic state? Location
As Fe2+ in duodenum
Related Flashcard Decks
Study Tips
- Press F to enter focus mode for distraction-free studying
- Review cards regularly to improve retention
- Try to recall the answer before flipping the card
- Share this deck with friends to study together
| Term | Definition |
|---|---|
Salivary Amylase Role MoA Yields | Starts digestion | Hydrolyzes α(1-4) linkages to yield disaccharides (maltose and α-limited dextrins) |
Pancreatic Amylase Concentrated in MoA | Highest concentration in duodenal lumen | Hydrolyzes starch to oligosaccharides and disaccharides |
Oligosaccharide Hydrolase Location Role MoA | At brush border of intestines Rate limiting step in carbohydrate digestion Produces monosaccharides from oligo- and disaccharides |
Carbohydrate absorption What kind of carbs? By what cells? What enzymes remove them from lumen? What enzymes transport them to the blood? | Only monosaccharides (glucose, galactose, and fructose are absorbed by enterocytes Glucose and Galactose are taken up by SGLT1 (Na dependent) Frucose taken up by facilitated diffusion through GLUT5 All sugars enter blood via GLUT2 |
How to distinguish GI mucosal damage from other causes of malabsorption? | D-xylose absorption test |
Iron absorption Ionic state? Location | As Fe2+ in duodenum |
Folate absorption | Location | Jejunum |
Peyer's Patches What are they? Where are they? Contain what kind of specialized cells? | Unencapsulated lymphoid tissue in LP and submucosa of ileum | Contains specialized M cells that take up antigen |
Peyer's Patches | What happens in germinal centers? Where do cells from germinal centers go? What do they do? | In germinal centers, B cells are stimulated to differentiate into IgA secreting plasma cells IgA cells migrate to LP IgA receives protective secretory component and is then transported across the epithelium to the gut to deal with intraluminal antigen |
Antibody in the gut? | Secretory IgA | "Intra Gut Antibody" |
Composition of Bile | Bild salts (bile acids conjugated to glycine and taurine to be made water soluble), Phospholipids, Cholesterol, Bilirubin, Water, Ions |
Rate limiting step in bile production | Cholesterol 7α hydroxylase |
Functions of Bile | Digestion and absorption of lipids and fat soluble vitamins Cholesterol excretion (the body's only means) Antimicrobial activity (via membrane disruption) |
Bilirubin Product of Removed from blood by Conjugated with Excreted in | Product of heme metabolism Removed from blood by liver Conjugated with glucuronate Excreted in bile |
Direct Bilirubin | Conjugated with glucuronic acid | Water soluble |
Indirect Bilirubin | Unconjugated | Water insoluble |
How is unconjugated bilirubin transported in the blood | Bound to albumin |
What enzyme conjugates bilirubin | UDP glucuronsyl transferase |
What happens to conjugated bilirubin in the gut? | Gut bacterial break it down into urobilinogen 80% of excreted in feces as stercobilin to give stool its brown color 20% is reabsorbed |
What happens to the reabsorbed urobilinogen? | 10% goes to kidneys and excreted in urine as urobilin (gives urine yellow color) 90% enters enterohepatic circulation |
Salivary Gland Tumor Dangerous? Common Location? | Generally benign and occurs in the parotid gland |
Salivary Gland Pleomorphic Adenoma Dangerous? Kind of tumor? Composition? Frequency? Presentation Recurrence? | Benign Mixed tumor of cartilage and epithelium Most common salivary gland tumor Painless and mobile mass Frequently recurs |
Warthin's Tumor Kind of tumor? Descriptive name? Dangerous? Description | Salivary Gland Tumor Papillary Cystadenoma Lymphomatosum Benign Cystic tumor with germinal centers |
Achalasia What is it? Presentation Diagnosis Increased Risk of... | Failure of the lower esophageal sphincter to relax due to loss of myenteric plexus Progressive dysphagia to solids and liquids Barium swallow shows dilated esophagus with area of distal stenosis (Birds Beak) Increased risk of squamous cell carcinoma |
Secondary Achalasia may arise from… | Chagas disease |