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Flashcards in Histology - Gastrointestinal Deck (71)
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What is the mouth lined by? 

Stratified squamous non-keratinising epithelium. Different from the skin (stratified squamous keratinised epithelium)


What are the 3 salivary glands?

Parotid, submandibular + sublingual gland


What are the salivary glands lined by?

Secretory glandular epithelium as they need to secrete saliva + enzymes 


What is the oesophagus lined by?

Stratified squamous non-keratinised epithelium


What glands does the oesophagus contain? 

Submucosal glands


What glands are found at the fundus of the stomach?

Gastric fundic mucosa = produce mucus


What does gastric body mucosa contain? 

Parietal cells = release hydrochloric acid and are source of intrinsic factor essential for absorption of vitamin B12


What else does gastric body mucosa contain? 

Chief cells = produce enzymes that start digestive process in stomach, e.g. pepsinogen, lipase


Is gastric antral mucosa as specialised?

No. Still has glands that produce protective layer of mucin, but not hydrochloric acid etc.


After the food has sat in the stomach, in reaches the intestines. What do the intestines do? 

- Digest food

- Absorb food

- Absorb water

- Resist bugs


What are the intestines lined by? 

- Cross sectionally, we have the lumen (where food is), then the mucosa (epithelial part = glandular epithelium). There are endocrine cells within this epithelium.


In the intestines, what comes after the mucosa?

- Submucosa = connective tissue



In the intestines, what comes after submucosa?

- Muscularis propria = all smooth muscle, contain ganglion cells (make the bowel move)


What are the interstitial cells of Cajal? 

- Found in muscular wall of intestine, pacemaker cells (ganglion cells make contractions, interstitial cells of Cajal pace this). 


In the intestine, what comes after muscularis proparia?

- Serosal surface (contains all the blood vessels) 


Image of layers of the bowel.


All of the intestine contains glandular mucosa, but this is arranged differently. What is the basic architecture of glandular mucosa? 

Crypts. At the bottom, you have stem cells. They produce transit cells, which are found further up. These transit cells eventually become columnar epithelial cells lining the gut


Anatomy of small intestine.


What does the duodenum do?

- Digests food (bile goes into duodenum, so there are digestive enzymes, bile salts etc.)

- Absorbs food

- Resists bugs


What is the main way that the small intestine increases surface area?

Villi, covered in epithelium. Microvilli found on villi. This is to maximise absorption


What is mucosa-associated lymphoid tissue (MALT)?

- Lymphocytes in the mucosa of the gut


What do the jejunum and ileum do?

- Digest food

- Absorb food

- Resist bugs

- They have microvilli as well to maximise SA for absorption 


In the appendix, what is the mucosa like?

Flat, no villi (absorption of food is more or less finished by the time it reaches the colon)


Anatomy of the large intestine (colon).


What does the colon do?

- Absorbs a bit of food

- Absorbs a bit of water

- Resists bugs


What is mucosa like in the colon? 

Flat glandular mucosa, no villi


The gut is a muscular tube. What is the general structure of the gut?


What is the one exception to this general structure?

The stomach. The muscularis propria has a innermost oblique layer, a middle circular layers and an outermost longitudinal layer


What is the tongue lined by?

Covered by stratified squamous non-keratinising epithelium on its ventral surface, but it is often heavily keratinised on its dorsal surface due to constant abrasion 


The dorsum of the tongue is thrown into complex folds known as what?

Papillae. Filiform = most common, cover anterior 2/3. Fungiform = tip + sides of tongue, taste buds embedded in epithelium on lateral sides of these papillae. Circumvallate separate anterior 2/3 and posterior 1/3 of tongue's surface, also contain taste buds