Gastrointestinal Histology Flashcards Preview

Gastrointestinal > Gastrointestinal Histology > Flashcards

Flashcards in Gastrointestinal Histology Deck (55):
1

What are the common structural features of the GIT?

mucosa, submucosa, muscularis externa, serosa/adventitia, neurons and immune cells

2

Which is the best structural feature to look at to determine which part of the GIT you’re in?

The mucosa

3

What is the mucosa?

The innermost layer of the GIT

4

What are the 3 layers of the mucosa?

epithelium, lamina propria, muscularis mucosae

5

What type of epithelium is in the mucosa?

simple columnar or stratified squamous

6

What is the lamina propria of the mucosa?

Loose connective tissue with nerves, blood vessels and immune cells

7

What type of muscle is in the muscularis mucosae?

a thin layer of smooth muscle - for mixing

8

At which part of the gut is there stratified squamous epithelium in the mucosa?

The oesophagus and the anus

9

At which part of the gut does the mucosa have a secretory structure?

The stomach and the large intestine - there are big pits of glands for secretion

10

At which part of the gut does the mucosa have an absorptive structure?

The small intestine - the mucosa has lots of folds

11

What is the submucosa?

A layer of dense, irregular connective tissue adjacent to the mucosa

12

What is the function of the submucosa?

Elasticity and structural support

13

What does the submucosa contain?

Nerves, small ganglia, blood vessels and sometimes glands and immune cells

14

What is the muscularis externa?

2 layers of muscle adjacent to the submucosa

15

What are the 2 layers of muscle?

The inner is circumferential and the outer is longitudinal

16

Where in the GIT is there 3 layers of muscle in the muscularis externa?

In the stomach

17

What ganglia are between the 2 layers of muscle?

The myenteric ganglia

18

What is the serosa/adventitia?

The outer surface of the gut

19

What is serosa?

A fluid secreting simple squamous epithelium to allow organ movement plus a thin layer of connective tissue

20

What is adventitia?

connective tissue joining GIT with surrounding structures e.g. at the oesophagus and rectum

21

What is the enteric nervous system?

The nervous system of the gut

22

What is the role of the myenteric ganglia?

To control smooth muscle activity

23

What is the role of the sub mucous ganglia?

To regulate absorptive and secretory processes

24

What type of epithelium is present in the oesophagus?

non-keratinised squamous epithelium

25

What are the two types of muscle in the oesophagus?

Striated at the top where contraction is voluntary and smooth at the bottom where contraction is involuntary

26

What is the z line?

The transition from oesophagus to stomach

27

How many layers of muscle are there in the stomach?

3

28

In what direction is the 3rd layer of muscle?

Oblique

29

What do mucous cells secrete?

mucous

30

What do parietal cells secrete?

hydrochloric acid

31

What do chief cells secrete?

pepsinogen

32

What do enteroendocrine cells secrete?

gastrin

33

Where in the gland are mucous cells?

At the surface and the neck of the gland

34

Where in the gland are parietal cells?

Scattered throughout the gland (except not at the top)

35

Where in the gland are chief cells?

at the base

36

Where in the gland are enteroendocrine cells?

very few throughout the base and neck

37

Can the different secretory cells be differentiated on a H&E stain?

No

38

How are the 3 regions of small intestine distinguished on H&E stain?

Their mucosa

39

What is plica circulares?

The macroscopically visible folded surface

40

What is a villus?

The folding on the plica circulares

41

What is a microvilli?

The folded surface on the enterocyte

42

What are the crypts of leiberkuhn?

The lumen between the villi where the glands empty into

43

What type of epithelium is there in the small intestine?

simple columnar

44

What cels are present in the epithelium of the small intestine?

enterocytes, goblet cells, enteroendocrine cells, paneth cells, stem cells

45

What are paneth cells?

cells which secrete antimicrobial peptides

46

What is in the lamina propria of the small intestine?

connective tissue, blood vessels, lymph and immune cells as well as extensions of the muscularis mucosae to move the villi

47

What is the distinctive feature of the duodenum?

Brunner’s glands

48

What are Brunner’s glands?

coiled glands in the submucosa that release alkaline mucus to negative acid from the stomach

49

What is the distinctive feature of the ileum?

Peyer’s patches

50

What are Peyer’s patches?

aggregates of lymph tissue in the submucosa

51

What is the taeniae coli?

3 bands of longitudinal muscle in the large intestine

52

Can the regions of the large intestine be distinguished histologically?

No

53

What does the mucosa of the large intestine look like?

There are no villi, long pits of glands and a layer of simple columnar epithelium

54

What cells are present in the epithelium of the large intestine?

enterocytes, goblet cells, enteroendocrine cells, stem cells

55

Are there more goblet cells in the small intestine or large intestine?

Large intestine