Gastroenterology IV

Question 1

What rare cancer is most closely associted with Celiac disease?

It is the result of proliferation of what type of cell?

Answer 1

T cell lymphoma

It is the result of proliferation of intraepithelial lymphocytes

Question 2

What two cell types are located within the Crypts of Lieverkuhn?

Answer 2

• Paneth cells
• Progenitor cells

Question 3

Where are Paneth cells located?
Describe their structure.

What is their function?

Answer 3

• location
  
  • base of crypts of lieerkuhn
• structure
  
  • columnar with eosinophilic granules
    
    • lysozyme
    • defensins
    • TNF alpha
      
      • also increases iCAM & selectin on WBC and endothelial cells (increase changes leukocytes to extravasate)
• function
  
  • control
    
    • bacteria

Question 4

How can you identify progenitor cells?

Why are they so hard to identify?

Where are they located?

What is their function?

Answer 4

• identify
  
  • mitotic figures
  • they are hard to identify becaus theya re undifferentiate cells (replace any cytes in epithelium)
  • bone marrow derived
• location
  
  • crypts of lieberkuhn
• function
  
  • replacement cells

Question 5

What is the most distinctive component ofthe lamina propria of the small intestine?

What is the lamina propria composed of?

Answer 5

• Loose connective tissue
• MALT/GALT (mucosa/gut associated lymphoid tisue)
  
  • diffuse lymphoid tissue (most distinctive)– in loose connective tissue
    
    • leukocytes
    • macrophages
  • scattered lymphoid follicles (aggregated into nodule)
    
    • duodenum and jejunum
  • Peyer’s patch
    
    • aggregated lymphoid follicles
    • antimesenteric side
    • ileum

Question 6

How is blood supplied to the small intestine lamina propria?

Answer 6

• capillary loops
  
  • from submucosa
  • into villus
  • collects soluble nutrients
    
    • amino acids and sugars

Question 7

Describe the lympatic composition of the small intestine lamina propria

Answer 7

• lacteal (lymph looks milk b/c lots lipids in it)
  
  • in villus
  • blind-ended capillary
  • collects chylomicra
• larger lymphatics
  
  • in submucosa

Question 8

What are the components of the submucosa of the small intestine?

Answer 8

• dense connective tissue
• vascular plexus
• Meissner’s plexus
• Brunner’s glands
  
  • only in duodenum
  • mucous glands
  • branched tubular
  • alkaline secretions
    
    • neutralize gastsric acid

Question 9

What are the components of the muscularis externa of the small intestine?

Answer 9

• muscularis externa
  
  • inner circular layer
  • outer longitudinal layer
  • auerbach’s plexus

Question 10

Which parts of the small intestine are covered wtih adventitia, whcih are covered with serosa?

Answer 10

• adventitia (retroperitoneal)
  
  • most of duodenum
• serosa (intraperitoneal)
  
  • jejunum
  • ileum
  • part of duodenum

Question 11

How can you identify the small intestine?

How cna differentiate between the different part of the small intestine?

Answer 11

• small intestine: villi
  
  • duodenum
    
    • submucosal glands
    • fewest goblet cells
  • jejunum (identify via exclusion)
    
    • tallest villi
  • ileum
    
    • most goblet cells
    • peyer’s patches
    • short villi
    • most goblet cells

Question 12

What are the regions of the large intestine?

What are the functions of the large intestine?

Answer 12

• Regions
  
  • cecum & appendix
  • colon
  • rectum
  • anal canal
• functions
  
  • reabsorption of
    
    • electrolytes
    • elimination of waste
• general struction same as rest of GI tract

Question 13

What is unique about the mucosa of the large intestine?

Describe the components of the mucosal epithelium.

Submucosa?

Answer 13

• mucosa
  
  • no villi!
• mucosal epithelium
  
  • same cells as in small intestine
  • no Paneth cells
  • Goblet cell are abundant
  • crypts of Lieberkuhn
    
    • same cells as surface
    • progenitor cells
    • if you see Paneth cells, you are looking at an inflamed bowel
• Submucosa: same as small intestine

Question 14

Describe the composition of the muscularis externa of the large intestine.

Answer 14

• Muscularis externa
  
  • inner circular layer
  • outer longitudinal lyer
    
    • teniae coli – distincitive feature of the colon
      
      • 3 thickened bands

Question 15

What is interesting about the serosa of the large intestine?

Answer 15

omental appendices (small fatty projections)

Question 16

What are the regional differences in the large intestine?

Answer 16

• colon
  
  • largest part
  • tenia coli
• vermiform appendix
  
  • aggregted lymphatic nodules
  • pr
• rectum
  
  • transverse rectal folds

image is the appendix