Histology of the GI Tract Flashcards
What is the basic histological organisation of the gut tube?
1) Lumen
2) Mucosa
- Epithelium (non-keratinized stratified squamous or simple columnar , secretion and absorption)
- Lamina propria (contains glands)
- Muscularis Mucosa (smooth muscle)
3) Submucosa (neurovascular and lymphatic supply to mucosa)
4) Muscularis externa (inner circular, outer longitudinal)
5) Serosa (Adventitia in eosophagus and anal)
What GI structure does this micrograph show? What are its distinguishing features?
Oesophagus
Submucosa shows mucous glands
Thick layers in order to transport solid food stuff
What GI structure is shown in this micrograph and what are its defining features?
Stomach
Thick muscular layers
Paritel cells (stain pink) - secrete HCl
Chief cells at base of glands - secrete pepsinogen
Gastric glands in mucosa
3 layers of muscle
What GI structure does the following micrograph show? What are its defining features?
Duodenum
Submucosa filled with glands (Brunners glands - ONLY found in Duodenum)
Broad villi
Peyers patches less common
What is the GI structure shown in this micrograph? What are its defining features?
Ileum
Increased amount of Peyers patches
What is the GI structure shown in this micrograph? What are its defining features?
Jejunum
Long thin villi
What is the GI structure shown in this micrograph? What are its defining features?
Large Intestine
Taenia Coli
Thick mucosa
No villi
Crypts
What structure is shown in this micrograph and what are its distinguishing features?
Pancreas
1 - Islets of Langerhans (no acini)
2 - Exocrine part (acini)
3 - Pancreatic duct
What structure is shown in the following micrograph and what are its distinguishing features?
Central vein
Hepatic cords
Bile canniliculus
How is the histological structure of the GI tract related to its function?
Eosophagus - Non-keratinized stratified squamous epithelium is strong enough to withstand the friction and pressure created by swallowing semi-solid foodstuff
Stomach - Thick muscular layers that act to breakup food and lots of gastric glands in mucosa that produce gastri juice
Small Intestine - Highly folded with plicae circularis and villi which massively increase the absorptive surface area
Large Intestine - Thick mucosa and lots of mucous secreting cells
Summarise the histological features of the eosophagus
1) Epithelium - Non-keratinized stratified squamous
2) Lamina propria - Mucus secreting
3) Muscularis mucosa - Longitudinal smooth muscle
4) Submucosa - Contains glands which secrete mucus
5) Muscularis propria:
- Upper 1/3 = skeletal muscle
- Middle 1/3 = skeletal + smooth muscle
- Lower 1/3 = smooth muscle
6) Adevntitia
Summarise the histological features of the stomach?
1) Epithelium - Simple columnar
2) Lamina propria - Gastric glands (parietal + chief cells)
3) Muscularis mucosae - Inner circular + Outer longitudinal smooth muscle
4) Submucosa - NO glands, Meisseners plexus
5) Muscularis Externa - Inner oblique, middle circular (pyloric sphincter), outer longitudinal
6) Serosa
Summarise the histological features of the small intestine
1) Epithelium - simple columnar with goblet cells
2) Lamina propria - crypts of lieberkuhn (goblet cells and paneth cells at base) and Peyers patches (especially in Ileum)
3) Muscularis Mucosa - Inner circular + outer longitudinal smooth
4) Submucosa - Duodenum contains Brunners glands
5) Muscularis externa - Inner circular + outer longitudinal
6) Serosa
Summarise the histological features of the large intestine
1) Epithelium - Simple columnar with goblet cells
2) Laminar propria - Crypts of Lieberkuhn
3) Muscularis Mucosae - Inner circular + outer longitudinal smooth muscle
4) Submucosa
5) Muscularis externa - Inner circular + outer longitudinal, Teniae coli (tense to form haustra)
6) Serosa - omental appendices, adventitia on ascending colon + descending colon
