Histology of GI

Question 1

what are the 4 basic types of tissue

Answer 1

1. epithelial tissue
2. connective tissue
3. muscle tissue
4. nervous tissue

Question 2

Tissue definition

Answer 2

a group of cells that work together and perform the same function (cells + extracellular substance)

Question 3

Organ definition

Answer 3

made up of two or more types of tissue

Question 4

Gut tube layers (in to out)

Answer 4

1. Mucosa (epithelium, lamina propria, musclularis mucosae)
2. Submucosa
3. Muscularis externa (inner circular, outer longitudinal)
4. adventitia/serosa

Question 5

Lamina propria

Answer 5

the loose connective tissue sitting just under the epithelium - rich in blood, lymph vessels

Question 6

Oesophagus

Answer 6

stratified squamous NON-KERATINISED epithelium

- submucosa shows mucous glands

Question 7

What type of muscle is in each third of the muscular layer of the oesophagus

Answer 7

upper 1/3 = skeletal
middle 1/3 = smooth + skeletal
lower 1/3 = smooth

Question 8

Stomach

Answer 8

Simple columnar epithelium - gastric glands in mucosa above muscularis mucosae

Question 9

Why does the surface epithelium of the stomach stain pale

Answer 9

due to presence of mucous - doesn’t hold stain well

Question 10

How many layers of muscle are in the muscular externa of the stomach

Answer 10

three - outer longitudinal, inner circular, innermost oblique

Question 11

Small intestine

Answer 11

simple columnar epithelium - villi, crypts of leikerkuhn, peyers patches

Question 12

Duodenum

Answer 12

simple columnar epithelium - characteristic brunners glands in submucosa

Question 13

Ileum

Answer 13

simple columnar epithelium - villi and peyers patches

Question 14

Jejunum

Answer 14

simple columnar epithelium - contains enterocytes and goblet cells

Question 15

Large intestine

Answer 15

Thick mucosa, crypts, mucous secreting cells, no villi

Question 16

three main glands in GI

Answer 16

Salivary glands, pancreas, liver

Question 17

Salivary glands

Answer 17

Secretory acini - roundish structure with columnar cells and nuclei at the base
Ducts seen also

Question 18

Pancreas

Answer 18

1. endocrine part - islets of langerhans (no acini)

2. exocrine part - pancreatic acini and pancreatic duct

Question 19

Liver

Answer 19

look for honeycomb shape?

Question 20

Muscularis mucosae

Answer 20

thin layer of smooth muscle

Question 21

epithelium

Answer 21

type varies with functions - basement membrane supports epithelium and not penetrated by blood vessels or nerve

Question 22

submucosa

Answer 22

collagenous supporting tissue - contains blood vessels, lymphatics and nerves

Question 23

muscularis propria

Answer 23

consists of smooth muscle layer (inner circular and outer longitudinal) - basis for peristaltic contraction
*stomach has an additional inner oblique muscle

Question 24

adventitia

Answer 24

loose supporting tissue - outside peritoneum

Question 25

serosa

Answer 25

visceral peritoneum - inside peritoneum

Question 26

Protective function (areas and epithelium type)

Answer 26

oral cavity, pharynx, oesophagus, anal canal - stratified squamous

Question 27

Secretory function (areas and epithelium type)

Answer 27

only seen in stomach - simple columnar with tubular glands

Question 28

Absorptive function (areas and epithelium type)

Answer 28

typical of entire small intestine - villi with short glands called crypts (brunners glands in duodenum)

Question 29

Absorptive + Protective function (areas and epithelium type)

Answer 29

lines the whole large intestine - closely packed straight tubular glands with goblet cells