GI Histology

Question 1

what kind of epithelium are the oral cavity, oropharynx and laryngopharynx lined with?

Answer 1

stratified squamous epithelium which is usually not keratinized

Question 2

what epithelium covers the tongue?

Answer 2

stratified squamous epithelium

Question 3

what part of the tongue has substantial lymphoid aggregates in the submucosa but lacks papillae?

Answer 3

posterior 1/3rd

Question 4

what part of the tongue has very thin epithelium on the ventral surface but has very thick epithelium covered in papillae on the dorsal surface?

Answer 4

anterior 2/3rds

Question 5

what papillae cover most of the dorsal surface?

Answer 5

filiform papillae

Question 6

the pharynx has a ring of _______ tissue composed of 4 different ____

Answer 6

lymphoid

tonsils

Question 7

name the 4 tonsils

Answer 7

palatine tonsils
lingual tonsils
tubal tonsils
pharyngeal tonsils (adenoids)

Question 8

what are the 4 components of the digestive tract wall?

Answer 8

mucosa
submucosa
muscularis externa
serosa or adventita

Question 9

what 3 layers make up the mucosa of the GI tract?

Answer 9

epithelium
lamina propria
muscularis

Question 10

what is the epithelium of the GI tract mucosa made of?

Answer 10

enterocytes which are epithelial cells specialised to absorb nutrients

Question 11

what is the lamina propria and what 3 things are contained within it?

Answer 11

loose connective tissue
capillaries
enteric neurones
lymphoid tissue

Question 12

what is the muscularis mucosae?

Answer 12

a thin smooth muscle layer

Question 13

what is the submucosa and what is its purpose?

Answer 13

connective tissue to give strength and elasticity to the digestive tract wall

Question 14

what does the submucosa contain? (4)

Answer 14

blood vessels
lymph vessels
glands
submucous plexus

Question 15

what are the 2 muscle layers of the muscularis externa?

Answer 15

circular muscle layer

longitudinal muscle layer

Question 16

what nerve plexus is contained within the muscularis externa?

Answer 16

myenteric plexus

Question 17

what are the 2 potential purposes of the serosa or adventitia?

Answer 17

suspend the digestive tract

attach components of it to other organs

Question 18

what layer of the digestive tract secretes a lubricating solution?

Answer 18

serosa

Question 19

what is the distinct histological change between the oesophagus and the stomach called?

Answer 19

gastro-oesophageal junction

Question 20

what changes between about the epithelium between the oesophagus and the stomach?

Answer 20

transitions from stratified squamous epithelium to simple columnar epithelium

Question 21

what is the isthmus?

Answer 21

the transition point between the gastric pit and gastric glands

Question 22

what is at the bottom of the gastric pits?

Answer 22

gastric glands

Question 23

what cells line the gastric pits and what are their purpose?

Answer 23

surface mucous cells that produced specialised mucus to protect against the acidic environment of the stomach

Question 24

what types of cells can be found in the gastric gland? (5)

Answer 24

parietal
stem 
chief
mucous
enteroendocrine

Question 25

shapes of ___ and ___ can determine the region of the stomach

Answer 25

pits | glands

Question 26

shape of pits and glands in the cardia of the stomach

Answer 26

deep pits | tortuous glands

Question 27

shape of pits and glands in the body/fundus

Answer 27

shallow pits | long straight glands

Question 28

shape of pits and gland in the pylorus

Answer 28

deep pits | high density of coiled and branched gastric glands

Question 29

what is special about the muscularis external of the stomach

Answer 29

it has an extra layer which aids the churning action of the stomach

Question 30

what do parietal cells secrete?

Answer 30

HCl

Question 31

what do chief cells release? (2)

Answer 31

pepsinogen (which is activated to produce pepsin) and gastric lipase

Question 32

what is the transition between the stomach and the duodenal mucosa marked by?

Answer 32

the pyloric sphincter

Question 33

what happens to the muscle of the stomach at the pyloric sphincter?

Answer 33

the circular smooth muscle of the stomach is enlarged

Question 34

what are the villi?

Answer 34

the projections on the mucosa of the small intestine

Question 35

what are the crypts of lieberkuhn?

Answer 35

the pits of the mucosa of the small intestine

Question 36

what is inside the villi?

Answer 36

lacteal which is a large lymphatic vessel that fat goes into instead of straight into the bloodstream

Question 37

what does the duodenum have to help it deal with acidic products from the stomach?

Answer 37

brunner's glands which produce an alkali mucus

Question 38

which of the 3 areas of intestine has the larges villi?

Answer 38

jejunum

Question 39

what are Peyer's patches and where are they located?

Answer 39

aggregations of lymphoid tissue in the ileum

Question 40

what is the most numerous absorptive cell with a brush border in the small intestine?

Answer 40

enterocyte

Question 41

what cells produce mucus to protect epithelium and lubricate the passageway of the small intestine?

Answer 41

goblet cells

Question 42

which cells are located at the base of the crypts of Lieberkuhn to produce antibacterial products in the small intesting?

Answer 42

paneth cells

Question 43

what cells produce hormones that contribute to the control of secretion and motility of the small intestine?

Answer 43

enteroendocrine cells

Question 44

what cells found at the base of the crypts of lieberkuhn replenish the epithelium?

Answer 44

stem cells

Question 45

what are the 2 main cell types which make up the mucosa of the large intestine?

Answer 45

``` absorptive cells (remove salts and watter) goblet cells (secretes mucus) ```

Question 46

what are the cells of the large intestine arranged into?

Answer 46

crypts

Question 47

what are the tendinae coli?

Answer 47

the 3 muscular strips the longitudinal muscle is found in along the large intestine

Question 48

what does the appendix have large amounts of?

Answer 48

lymphoid tissue

Question 49

what epithelium is the anal canal lined with and what does this transition into?

Answer 49

non-keratinized stratified squamous epithelium which is then continuous with the keratinized epithelium of the skin

Question 50

non-keratinized stratified squamous epithelium is _____ and found in _____ (4)

Answer 50

protective | oral cavity, pharynx, oesophagus, anal canal

Question 51

simple columnar epithelium with villi and tubular glands is ____ and found in ______

Answer 51

absorptive | small intestine

Question 52

simple columnar epithelium with extensive tubular cells is _____ and found in _____

Answer 52

secretory | stomach

Question 53

simple columnar epithelium with some tubular glands is _____ and _____ and is found in ________

Answer 53

protective and absorptive | large intestine

Question 54

what is the liver parenchyma composed of?

Answer 54

glandular epithelial cells

Question 55

name 4 of the many functions of the liver

Answer 55

``` regulate blood glucose levels detoxification glycogen storage synthesis of and secretion of bile (and many other metabolic functions) ```

Question 56

what is the opening at the hilum of the liver called?

Answer 56

porta hepatis

Question 57

what enters the liver through the porta hepatis?

Answer 57

portal triad

Question 58

the liver has a _____ tissue capsule covered by ______ cells

Answer 58

``` collagenous connective mesothelial cells (simple squamous epithelium) ```

Question 59

the liver is made up of hexagonal shaped _____

Answer 59

lobules

Question 60

what is at the centre of each lobule?

Answer 60

central vein (which is a branch of the hepatic vein)

Question 61

what is at the corners of all the lobules?

Answer 61

portal triads

Question 62

_____ _____ percolate into the central vein

Answer 62

hepatic sinusoids

Question 63

what does the portal triad contain? (5)

Answer 63

``` bile ductule (for bile to exit) hepatic portal vein hepatic artery usually contains lymph vessels is also companied by collagenous connective tissue ```

Question 64

the hepatic artery supplies the liver with ________

Answer 64

oxygenated blood

Question 65

the hepatic portal vein carries _____, _______ blood form the spleen, stomach and intestine

Answer 65

deoxygenated, nutrient rich

Question 66

the hepatic vein takes ______ blood from the liver to the ___

Answer 66

deoxygenated | IVC

Question 67

what are sinusoids?

Answer 67

gaps between hepatocytes that blood flows through

Question 68

sinusoids receive blood from the _____ and _____ and deliver it to the central vein

Answer 68

hepatic artery | portal vein

Question 69

what is the space between the sinusoid and the hepatocytes called?

Answer 69

perisinusoidal space

Question 70

where are hepatic stellate cells found and what do they do?

Answer 70

in the perisinusoidal space that are modified fibroblasts that make connective tissue which supports the liver

Question 71

what are Kupffer cells and what do they do?

Answer 71

they are macrophages resident in the lining of sinusoids that help to remove red blood cells

Question 72

what is bile and what does it contain? (5)

Answer 72

alkaline solution | water, ions, phospholipids, bilirubin, bile salts

Question 73

bile is critical for the absorption of ___ and ____ vitamins

Answer 73

fat and fat-soluble vitamins

Question 74

what are cholangiocytes?

Answer 74

the simple cuboidal epithelial cells of the biliary tree and are responsible for modifying primary bile

Question 75

how is bilirubin pigment produced?

Answer 75

breakdown of haemoglobin

Question 76

bile salts are necessary for what?

Answer 76

emulsification of fats

Question 77

what cells produce bile?

Answer 77

hepatocytes

Question 78

how does bile reach the portal triad?

Answer 78

it travels via bile canaliculi (which are formed by tight junctions in the cell membranes of adjacent hepatocytes)

Question 79

the gall bladder is a _____ pouch that sits under the ____

Answer 79

muscular | liver

Question 80

name the components of the gall bladder lining (4)

Answer 80

simple tall columnar epithelium with a brush border lamina propria (rich in blood and lymphatic vessels) smooth muscle outer layer of collagenous adventitia

Question 81

the gall bladder ___ and ___ bile

Answer 81

stores | modifies

Question 82

the gall bladder is stimulated to contract by ____ and _____ control to release bile into the duodenum

Answer 82

nervous (vagal) | hormonal

Question 83

what is released by the duodenum when fatty food enters it to stimulate the contraction of the gall bladder?

Answer 83

cholecystokinin

Question 84

what is cholecystitis?

Answer 84

inflammation of the gall bladder

Question 85

what can the obstruction of the cystic duct by gall stones lead to? (3)

Answer 85

expansion of the gall bladder, thickening of the muscle layers, inflammation

Question 86

what is the parenchyma of the pancreas composed of?

Answer 86

glandular epithelial cells

Question 87

the pancreas is an _____ and ______ ____

Answer 87

exocrine and endocrine gland

Question 88

what does the exocrine pancreas produce?

Answer 88

digestive juices

Question 89

the majority of the pancreatic tissue is exocrine/endocrine?

Answer 89

exocrine

Question 90

the enzymes secreted by the exocrine pancreas are secreted as ______

Answer 90

inactive proenzymes

Question 91

what activates the enzymes produced by the pancreas?

Answer 91

trypsin (the active form of trypsinogen)

Question 92

what is an acinus?

Answer 92

a small cavity surrounded by the secretory cells of a gland

Question 93

what are centroacinar cells?

Answer 93

extension of the intercalated duct cells into the acinus

Question 94

what are islands of tissue scattered around the pancreas and what do they produce?

Answer 94

``` islets of langerhans produce hormones (e.g. insulin, glucagon) ```

Question 95

what is the hepatopancreatic ampulla (of Vater)?

Answer 95

where the main pancreatic duct joins the common bile duct and opens into the duodenum on a papillae

Question 96

what are zymogen granules?

Answer 96

storage granules in the exocrine pancreas for sorting, packaging and regulating the secretion of digestive enzymes

Question 97

what are the exocrine cells of the pancreas called?

Answer 97

acinar cells