GI - histology

Question 1

what kind of epithelium is found in oral cavity, oropharynx and larygopharynx

Answer 1

stratified squamous epithelium

Question 2

describe the epithelium on the dorsal/ventral surfaces of the tongue

Answer 2

anterior 2/3 
ventral - thin
dorsal - thick with papilla
posterior 1/3
dorsal - smooth stratified squamous epithelium which lacks papillae except circumvallate but has substantial lymphoid aggregates in submucosa

Question 3

describe the epithelium of the nasal cavity and nasopharynx

Answer 3

ciliated pseudostratified columnar epithelium with goblet cells (respiratory)

Question 4

what are the 4 papilla found in tongue and which isn’t used for taste

Answer 4

fungiform
circumvallate
filiform - not taste
foliate

Question 5

where are submucosal glands found

Answer 5

submucosa of oesophageal lining and duodenum

Question 6

what is the Z line and what gives it its appearance

Answer 6

gastro-oesophageal junction

stratified squamous epithelium to columnar epithelium

Question 7

where are gastric pits found and what do they contain

Answer 7

found in mucosa of stomach cells, lined by surface mucous cells which contain gastric glands - parietal cells and chief cells

Question 8

what do parietal cells secrete

Answer 8

intrinsic factor and HCL

Question 9

what do chief cells secrete

Answer 9

pepsinogen

Question 10

where in the stomach does the smooth muscle thickness of the muscularis external increase

Answer 10

pyloric sphincter

Question 11

what are villi

Answer 11

finger like projections found on mucosa of small intestine surfaces

Question 12

what are crypts of lieberkuhn

Answer 12

pits found next to villi on small intestinal mucosa and in large intestine

Question 13

what kind of cells are enterocytes

Answer 13

main absorptive cells of small intestine

tall columnar cells with brush border

Question 14

what kind of cells are goblet cells

Answer 14

small intestinal glands that produce mucin which protects and lubricates cells and moves things along

Question 15

what is the function of paneth cells

Answer 15

antibacterial function

Question 16

what is the function of enteroendocrine cells

Answer 16

produce hormones to control gastrin secretion and motility

CCK, VIP, Gastrin

Question 17

where are stem cells found in the gut

Answer 17

bottom of crypts of lieberkuhn

Question 18

what are brunners glands

Answer 18

found in duodenum

release alkaline mucous to neutralise HCL in chyme

Question 19

where are the tallest villi found in small intestine

Answer 19

jejeunum

Question 20

what are the 4 main layers of the GI tract

Answer 20

mucosa
submucosa
muscularis externa
serosa/adventitia

Question 21

what is the mucosa made up of

Answer 21

epithelium (sits on basal lamina) - absorption

exocrine cells
endocrine gland cells

lamina propria (loose connective tissue) - capillaries, enteric neurones and immune cells

muscularis mucosa (thin layer of SM) - contraction causes changes in absorptive and secretory area of mucosa - facilitates absorption

Question 22

what makes up the submucosa

Answer 22

loose connective tissue

larger blood and lymph vessels

Question 23

what makes up the muscularis externa

Answer 23

circular (inner) and longitudinal muscle (outer)

myenteric plexus

Question 24

what are the 3 layers of longitudinal muscle called in the large intestine

Answer 24

teniae coli

Question 25

what is the serosa/adventitia

Answer 25

outer layer of connective tissue that either suspends digestive tract or attaches it to other organs

Question 26

true/false

the appendix has a lot of lymphoid tissue

Answer 26

true

Question 27

what are the 2 nerve plexuses of the enteric nervous system and where are they found

Answer 27

submucosal plexus (in submucosa)
myenteric plexus (between circular and longitudinal muscle of muscularis externa)

Question 28

what do oxyntic cells look like

Answer 28

pink fried eggs with purple yolks

Question 29

what is a Schatzki’s ring

Answer 29

beginning of a stricture

Question 30

how do the myenteric and submucosal plexuses connect

Answer 30

interganglionic fibre tracts