Gastrointestinal Histology

Question 1

What are the common structural features of the GIT?

Answer 1

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

Question 2

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

Answer 2

The mucosa

Question 3

What is the mucosa?

Answer 3

The innermost layer of the GIT

Question 4

What are the 3 layers of the mucosa?

Answer 4

epithelium, lamina propria, muscularis mucosae

Question 5

What type of epithelium is in the mucosa?

Answer 5

simple columnar or stratified squamous

Question 6

What is the lamina propria of the mucosa?

Answer 6

Loose connective tissue with nerves, blood vessels and immune cells

Question 7

What type of muscle is in the muscularis mucosae?

Answer 7

a thin layer of smooth muscle - for mixing

Question 8

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

Answer 8

The oesophagus and the anus

Question 9

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

Answer 9

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

Question 10

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

Answer 10

The small intestine - the mucosa has lots of folds

Question 11

What is the submucosa?

Answer 11

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

Question 12

What is the function of the submucosa?

Answer 12

Elasticity and structural support

Question 13

What does the submucosa contain?

Answer 13

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

Question 14

What is the muscularis externa?

Answer 14

2 layers of muscle adjacent to the submucosa

Question 15

What are the 2 layers of muscle?

Answer 15

The inner is circumferential and the outer is longitudinal

Question 16

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

Answer 16

In the stomach

Question 17

What ganglia are between the 2 layers of muscle?

Answer 17

The myenteric ganglia

Question 18

What is the serosa/adventitia?

Answer 18

The outer surface of the gut

Question 19

What is serosa?

Answer 19

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

Question 20

What is adventitia?

Answer 20

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

Question 21

What is the enteric nervous system?

Answer 21

The nervous system of the gut

Question 22

What is the role of the myenteric ganglia?

Answer 22

To control smooth muscle activity

Question 23

What is the role of the sub mucous ganglia?

Answer 23

To regulate absorptive and secretory processes

Question 24

What type of epithelium is present in the oesophagus?

Answer 24

non-keratinised squamous epithelium

Question 25

What are the two types of muscle in the oesophagus?

Answer 25

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

Question 26

What is the z line?

Answer 26

The transition from oesophagus to stomach

Question 27

How many layers of muscle are there in the stomach?

Answer 27

3

Question 28

In what direction is the 3rd layer of muscle?

Answer 28

Oblique

Question 29

What do mucous cells secrete?

Answer 29

mucous

Question 30

What do parietal cells secrete?

Answer 30

hydrochloric acid

Question 31

What do chief cells secrete?

Answer 31

pepsinogen

Question 32

What do enteroendocrine cells secrete?

Answer 32

gastrin

Question 33

Where in the gland are mucous cells?

Answer 33

At the surface and the neck of the gland

Question 34

Where in the gland are parietal cells?

Answer 34

Scattered throughout the gland (except not at the top)

Question 35

Where in the gland are chief cells?

Answer 35

at the base

Question 36

Where in the gland are enteroendocrine cells?

Answer 36

very few throughout the base and neck

Question 37

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

Answer 37

No

Question 38

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

Answer 38

Their mucosa

Question 39

What is plica circulares?

Answer 39

The macroscopically visible folded surface

Question 40

What is a villus?

Answer 40

The folding on the plica circulares

Question 41

What is a microvilli?

Answer 41

The folded surface on the enterocyte

Question 42

What are the crypts of leiberkuhn?

Answer 42

The lumen between the villi where the glands empty into

Question 43

What type of epithelium is there in the small intestine?

Answer 43

simple columnar

Question 44

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

Answer 44

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

Question 45

What are paneth cells?

Answer 45

cells which secrete antimicrobial peptides

Question 46

What is in the lamina propria of the small intestine?

Answer 46

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

Question 47

What is the distinctive feature of the duodenum?

Answer 47

Brunner’s glands

Question 48

What are Brunner’s glands?

Answer 48

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

Question 49

What is the distinctive feature of the ileum?

Answer 49

Peyer’s patches

Question 50

What are Peyer’s patches?

Answer 50

aggregates of lymph tissue in the submucosa

Question 51

What is the taeniae coli?

Answer 51

3 bands of longitudinal muscle in the large intestine

Question 52

Can the regions of the large intestine be distinguished histologically?

Answer 52

No

Question 53

What does the mucosa of the large intestine look like?

Answer 53

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

Question 54

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

Answer 54

enterocytes, goblet cells, enteroendocrine cells, stem cells

Question 55

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

Answer 55

Large intestine