Trávicí trakt II.

Digestive tube
Gastrointestinal tract II.
Histology and embryology
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Esophagus
Ventricle - gaster
Small intestine
Large intestine
Rectum
Anus
Esophagus
– stratified squamous nonkeratinising
epithelium
– lamina propria mucosae – distally esophageal
cardial glands
– in submucosis mucinous glands - gl.
oesophagicae
– proximally skeletal musculature
– adventitia – serosa only in short abdominal
part
Gaster
• tunica mucosa
– areae gastricae → foveolae gastricae
– simple columnar epi - mucous production
– lamina propria mucosae
• gastrical glands, lymphatic follicles
• tunica muscularis
– inner - fibrae obliquae
– medial - circular - m. sphincter pylori
– outer - longitudinal
Tunica mucosa of gaster
• gastric pits
• deeper in pyloric part
• glands enter these pits
– gl. cardiacae - deep
– gl. gastricae propriae
– gl. pyloricae – shallow
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Gastric cells
• main cells- pepsinogen, lipase
• parietal cells- HCl, intrinsic factor
• abundant intracellular channels
Synthesis of HCl
• in parietal cells
• Cl- - from plasma
• H+ - from H2CO3
– by carboanhydrase from CO2 and H2O
• mucinous cells – mucous
• enteroendocrine cells - gastrin,
somatostatin
• undiferentiated cells - mitotically active
Intestinum tenue
(= small intestine)
• duodenum
• jejunum
• ileum
mesenterium - radix mesenterii
Tunica mucosa of small int.
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plicae circulares (Kerkringi) → villi
Crypts of Lieberkühn
simple columnar epithelium
lamina propria mucosae
– vessels, smooth muscles, lymph. foll.
plicae circulares, villi intestinales
Cells of small int. mucosa
• enterocytes - resorption
– microvilli, interdigitations, lipid droplets
• goblet cells – mucus production
• Paneth cells – lysozym production
• endocrine cells - 12 types
– cholecystokinin, sekretin
• M-cells - over Peyer‘s plates (later)
• undiferentiated cells
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Villi
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digit- to leaf-formed elements
about 10times surface enlargement
surface – enterocytes, goblet cells
smooth muscle „skeleton“
lot of capillaries
lymphatic, so called lacteal vessels
Mucosa of large intestine
• no folds and villi
• crypts of Lieberkühn are deeper
– enterocytes – less of microvilli
– goblet cells are numerous
– Paneth cells are missing
– endocrine cells are present
Appendix vermiformis
• Paneth cells are present
• lamina propria mucosae
– fulfilled with lymphatic tissue = noduli
lymphoidei aggregati („tonsilla abdominalis“)
• longitudinal musculature surrounds it
completely – no taenie
Other layers of small int. wall
• Tela submucosa
– in duodenum – glands of Brunner
• tuboalveolar mucinous
• alkalic secretion
– mainly in ileum – Peyer‘s plates
• acumulation of lymphatic tissue
• other layer correnspond to standard form of git
tube
Other layers of large intestine
wall
• tunica muscularis externa
– inner circular - haustrations
– outer longitudinal – reduced to taenie coli
• tunica serosa
– appendices epiploicae – adipous tissue
Intestinum rectum
• pars pelvina
– plicae transversales recti - semilunar
– contains circular muscle layer
• canalis analis
– zona haemorrhoidalis - m. sphincter ani int.
• columnae anales (6-10)
• change of epithelium – stratified squamous nonkeratinising
• anal plexus – cavernous body
– zona cutanea – keratinising epithelium
• glandulae circumanales (sweat and apocrine)
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