Gastrointestinal tract 4

Question 1

99. Ileum (HE)

Answer 1

• EPITHELIUM: columnar enterocytes
  
  • crypts of Lieberkühn
  • goblet cells
  • lymphocytes
• LAMINA PROPRIA:
  
  • hihly vascular loose cellular CT
  • penetrates core of intestinal villi with arteriole + central lymphatic vessel + smooth muscle
  • fibroblasts, leukocytes, macrophages, mast cells, lymphocytes, plasma cells
• MUSCULARIS MUCOSA: inner circular, outer longitudinal
• SUBMUCOSA:
  
  • Meissner’s plexus
  • large ganglion cells
  • no glands
  • circular folds of Kerckring
• MUSCULARIS EXTERNA: Auerbach’s plexus, inner circular + outer longitudinal smooth muscle
• SEROSA: simple squamous mesothelial cells + CT

Question 2

Paneth cell

Answer 2

• in crypts of Lieberkühn
• exocrine serous glandular cells
• eosinophilic granulation

Question 3

67. Ileum -Peyer’s patches (HE)

Answer 3

Peyer’s patches:

• 10-300 round lymphoid follicles
• located in lamina propria and submucosa
• situated in anti-mesenteric wall
• dome areas devoid of villi and crypts of lieberkuhn ⇒ low columnar or cuboidal cells overlie their surface
• no goblet cells
• Microfold cella (M-cells)- epithelial cells making pockets⇒ T-cells and APC migrate into pockets

Question 4

68. Colon (HE)

Answer 4

• no circular folds of Kerckring or intestinal villi
• tenia on outside, haustra + semilunar folds
• EPITHELIUM: columnar absorptive cells + goblet cells
• LAMINA PROPRIA:
  
  • closely packet crypts of Lieberkühn
  • narrow lumens, lined by goblet cells, enterocytes, enteroendocrine cells, stem cells
  • CT separates tubular glands
• MUSCULARIS MUCOSA: inner circularm outer longitudinal
• SUBMUCOSA: devoid of glands
• MUSCULARIS EXTERNA: inner circular, outer longitudinal + tenia coli
• SEROSA: subserosal CT, fat-filled appendices epiploicae

Question 5

69. Vermiform appenxid (HE)

Answer 5

• dense all round filtration of lymphatic tissue
• lymphoid follicles in lamina propria and submucosa
• EPITHELIUM: columnar enterocytes, goblet cells, M-cells
• crypts of Lieberkühn- less closely + shorter
• Paneth cells