Gastrointestinal tract 3

Question 1

5. Esophagus (HE)

Answer 1

• EPITHELIUM: non-keratinized stratified squamous + lymphocytes
• LAMINA PROPRIA:
  
  • thin dense CT
  • vascular CT papillae
  • lymphocytes
  • mucous glands
  • esophageal cardiac glands (near cardiac orifice) ⇒ neutral mucin
• MUSCULAR MUCOSA: longitudinal smooth muscle (increases downwards)
• SUBMUCOSA:
  
  • loose, highly vascular CT + elastic fibers
  • small mucous glands
• MUSCULARIS EXTERNA: outer longitudinal ⇒ inner circular
  
  • upp: visceral striated muscle
  • down: smooth muscle
  • Auerbach’s plexus
• SEROSA/ADVENTITIA: CT

Question 2

62. Stomach- fundus (HE)

Answer 2

• EPITHELIUM: simple, tall columnar + mucous secreting cells + gastric pits
• LAMINA PROPRIA:
  
  • gastric glands
  • chief, parietal, mucous neck cells, stem cells, enteroendocrine cells
• MUSCULARIS MUCOSA: bilayered smooth muscle bundles⇒ inner circular, outer longitudinal
• SUBMUCOSA: loose CT, blood and lymph vessels, lymphocytes, macrophages, mast cells, Meissner’s plexus, collagen, elastic fibers
• MUSCULARIS EXTERNA: inner oblique ⇒ middle circular ⇒ outer longitudinal muscle layer + Auerbach’s plexus
• SEROSA: simple, squamous mesothelial cells + CT

Question 3

Chief cells

Answer 3

• high cuboidal
• basal third of gastric glands
• secrete pepsinogen ⇒ pepsin
• strong basophilia in basal cytoplasm ⇒ rER
• apical lighter ⇒ secretory granules
• round nucleus basally located

Question 4

Parietal cells

Answer 4

• upper and middle third of gastric glands
• large, ovoid/rounded triangular shaped cells
• acidophilia
• round nucleus centrally
• secrete HCl + Intrinsic factor

Question 5

Mucous neck cell

Answer 5

• in neck and isthmus

- secrete less viscous mucous than surface cells

Question 6

Undifferentiated stem cells

Answer 6

• low columnar, highly mitotic cells
• in isthmus + base of gastric glands
• differentiate to surface mucous cells, neck mucous cells, chief cells, parietal cells, enteroendocrine cells

Question 7

Enteroendocrine cells

Answer 7

• basal part of gastric glands
• lie in basal membrane
• small and weakly stained

Question 8

63. Esophago-Gastric junction (HE)

Answer 8

• EPITHELIUM:
• esophagus: non-keratinized stratified squamous
• stomach: simple columnar + mucous secreting cells + gastric pits
• LAMINA PROPRIA:
• esophagus: esophageal cardiac glands
• stomach: cardiac glands
• MUSCULARIS MUCOSA:
• esophagus: weblike orientation of smooth muscle
• stomach: bilayered smooth muscle, inner circular, outer longitudinal
• SUBMUCOSA: large blood vessels, Meissner’s plexus, collagen, elastic fibers
• MUSCULARIS EXTERNA:
• esophagus: inner circular, outer longitudinal
• stomach: inner oblique, middle circular and outer longitudinal
• SEROSA: simple squamous mesothelial cells + CT

Question 9

65. Duodenum (HE)

Answer 9

• EPITHELIUM: columnar enterocytes + goblet cells + microvilli
• LAMINA PROPRIA:
  
  • crypts of Lieberkühn
  • intestinal villi
  • goblet cells, stem cells, enteroendocrine cells, Paneth cells
• MUSCULARIS MUCOSA: inner circular ⇒ outer longitudinal smooth muscle
• SUBMUCOSA:
  
  • Brunner’s glands
• MUSCULARIS EXTERNA:
  
  • Auerbach’s plexus
  • inner circular, outer longitudinal smooth muscle
• SEROSA: simple squamous mesothelial cells + CT

Question 10

Plicae circulars of Kerckring

Answer 10

• size 4-8mm
• transverse circular folds projecting into lumen
• submucosal CT core

Question 11

Intestinal and microvilli

Answer 11

• intestinal villi:
• size: 0,5-1,5 mm
• finger-like projections of mucosa
• large and numerous in duodenum and jejunum
• microvilli:
• size: 1-1,4 um
• projections of apical plasma membrane of the enterocytes
• cytoplasmic core ⇒ actin filaments

Question 12

Brunner’s glands

Answer 12

• compund tubulo-acinar mucous type
• acini lined by high cuboidal cells
• secretory product less acidic than goblet cell
• duct open in crypt of Lieberkühn

Question 13

66. DUodenum (alcain blue-H picrosiriusred stain)

Answer 13

• stains the acid mucopolysaccharides of Goblet cells secretion ⇒ greenish blue
• mucus of Brunner’s gland contain bicarbonate ions, neutral and alkaline glycoproteins
• secretory cells ⇒ yellow
• cell nuclei ⇒ blue/brown

Question 14

64. Pylorus (HE)

Answer 14

• EPITHELIUM: columnar mucus secreting cells ⇒ columnar enterocytes
• SUBMUCOSA: Brunner’s glands + intestinal vili indicate duodenum
• MUSCULARIS EXTERNA: middle circular ⇒ pyloric sphincter