Histology of Alimentary Tract Flashcards Preview

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Flashcards in Histology of Alimentary Tract Deck (26)
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0
Q

What does “mucosa” refer to in the GI tract?

A

The innermost 3 layers: epithelium, lamina propria, muscularis .

1
Q

7 layers of tissue in the GI tract, from inside out?

A
Epithelium
Lamina propria
Muscularis mucosae
Submucosae
Inner muscle layer (circular)
Outer muscle layer (longitudinal)
Adventitia or serosa
2
Q

Where are the 2 layers of nerve plexuses?

A

In the submucosal layer (Meisner’s)

Between the muscularis propria layers (Meyenteric / Auerbach’s)

3
Q

CTB review: 3 ways to stick cells together?

A

Tight junctions
Desmosomes
Gap junctions

4
Q

Why are there acini in the esophagus?

A

To secrete saliva, to keep the esophagus lubricated.

5
Q

3 different histological regions of the stomach? (slightly different from Dr. White’s divisions)

A

Cardia
Corpus
Antrum

6
Q

What are the little dots on the rugae?

A

Gastric pits, where glandular cells live.

7
Q

Which cells make stomach acid?

A

Parietal cells.

8
Q

What tells the parietal cells to make acid?

A

Gastrin and histamine.

9
Q

What cells make gastrin?

A

Antral neurendocrine cells (G cells)

10
Q

What cells make histamine, and what tells them to do so?

A

Enterochromaffin-like cells make histamine in response to gastrin.
(histamine acts paracrine)

11
Q

Should there be inflammatory cells in the lamina propria of the stomach?

A

No.

12
Q

What do parietal cells look like on H&E?

A

Very pink cytoplasm.

“P” for parietal, pink, and pH

13
Q

What do chief cells make?

A

Digestive enzymes, such as pepsinogen.

14
Q

Where are the parietal cells mostly?

A

In the corpus/fundus (less so in the antrum).

15
Q

Where in the GI tract is most of the lymphoid aggregation?

A

In the ileum and colon.

16
Q

Should T cells be in the epithelium of the small intenstine?

A

Apparently not.

17
Q

What are the lymph vessels of the lamina propria called?

A

Lacteals

18
Q

What do paneth cells look like? What do they do? Where are they?

A

Eosinophilic granules, secrete microbial peptides, in the “small intestine”

19
Q

What do Brunner glands do? What layer are they in? Where are they found?

A

These are submucosal glands of the duodenum that secrete alkaline stuff to neutralize acid chyme.

20
Q

What does the colon absorb?

A

Water, Na+, Cl-

when colon is inflamed and can’t absorb well, water stays in lumen -> diarrhea

21
Q

Why is it significant that the lymphatics of the colon are so deep?

A

Cancer takes a long time to invade that deeply to metastasize.
(contrasted with small intestine)

22
Q

What are the lymphocyte follicles in the small intestine called?

A

Peyer’s patches

23
Q

What special cells are antigens in the gut lumen transcytosed through? (How do they look different from other epithelial cells?)

A

M cells. They don’t have microvilli (no brush border).

24
Q

What do B cells in the gut make a lot of? Proposed function?

A

They make a lot of IgA and IgM.

These are thought to be very important in preventing pathogens from adhering to the gut epithelium.

25
Q

Do the esophagus and stomach normally have lymphoid tissue?

A

Nope.