15. Histology of GIT + associated organs

Question 1

3 major salivary glands

Answer 1

1) Parotid 2) Submandibular 3) Sublingual

Question 2

Functions of saliva

Answer 2

to moisten the mucosa and food before swallowing

high bicarbonate content buffers the oral cavity → stimulate taste buds

begins the digestion of carbohydrates via amylase

controls bacterial flora by secreting lysozyme

secrete IgA and potassium

resorbs sodium

Question 3

3 types of ducts

Answer 3

1) Intercalated 2) Striated (secretory) 3) Excretory

Question 4

Intercalated duct

Answer 4

secrete bicarbonate ion (HCO3-)

absorb chloride ion (Cl-)

Question 5

Striated (secretory) duct

Answer 5

secrete K+

absorb Na+

Question 6

Answer 6

Sialosis

non inflamatory enlargment of parotids

caused by excess alcohol use.

Question 7

Answer 7

Benign tumour of the left parotid gland

producing characteristic deflection of the ear lobe

Question 8

Parasympathetic innervation of salivary glands

Answer 8

cranial nerves: 7 & 9

Question 9

Sympathetic innervation of Salivary glands

Answer 9

pre-ganglionic nerves in: T1-T3

Question 10

Epithelium of digestive tract

Answer 10

ends: non-keratinised stratified squamous

in between: simple columnar

Question 11

Oesophagus

Answer 11

Non-keratinised stratified squamous epithelium

Only lowest portion has Serosa

Question 12

Rugae (stomach)

Answer 12

allow stomach to expand

Question 13

Gastric pits (Stomach)

Answer 13

Hole like depressions between villi

ductal openings of stomach glands

Question 14

Epithelium of stomach

Answer 14

simple columnar

has no goblet cells

Parietal Cells ( produce Acid and Intrinsic factor)

Chief Cells (pepsinogen)

Question 15

Lamina propria (stomach)

Answer 15

abundant glands

secrete mucus

Question 16

Functions of the small bowel

Answer 16

Main site of digestion and secretion

Question 17

Coeliac Disease

Answer 17

Autoimmune

destruction of the small bowel villi

due to gluten exposure

Gliadin is presented by APCs on MHC Class II

leads to T Helper Cell mediated tissue damage

Flattening of the villi, Hyperplasia of Crypts and increase in interepithelial lymphocytes

Question 18

Adaptations of Duodenum: Shortest Segment

Answer 18

Long-leaf-like villi

Brunner’s Glands

Question 19

Order of number of Plicae Circulares (most to least)

Answer 19

1) Jejunum
2) Duodenum
3) Ileum

Question 20

Adaptations of Ileum

Answer 20

↑ number of Goblet cells

↑ Peyer’s Patches and M cells

Question 21

Teniae coli in the Colon

Answer 21

three visible strips of longitudinal muscle

aid in peristalsis

everywhere except appendix and rectum

Question 22

Haustra in the colon

Answer 22

small saccules of large intestine

Help move faeces in segmental fashion

Question 23

What adaptations are NOT found in the Colon?

Answer 23

plicae

villi

Question 24

Mucosa of colon

Answer 24

thin

columnar Epithelium

simple tubular glands → crypts → produce mucus

Question 25

Largest internal organ

Answer 25

Liver

Question 26

Hepatocytes

Answer 26

Large polygonal cells form plates of hepatic lobule

Question 27

Hepatocyte Function

Answer 27

Protein synthesis Protein storage Transformation of carbohydrates Synthesis of cholesterol, bile salts and phospholipids Detoxification Formation and secretion of bile.

Question 28

What percentage of the liver's cytoplasmic mass do hepatocytes make up?

Answer 28

70-85%

Question 29

Sinusoids

Answer 29

endothelium with large gaps between cells incomplete basement membrane

Question 30

Where are sinusoids found? (4)

Answer 30

Liver Spleen Adrenal Medulla Bone Marrow

Question 31

Kupffer Cells (liver)

Answer 31

macrophages

Question 32

Stellate cells (liver)

Answer 32

Found in Space of Disse Store fats, Vits A,D,E,K B12 Secrete ECM

Question 33

What produces bile?

Answer 33

hepatocytes

Question 34

The Bile duct

Answer 34

carries bile → gallbladder

Question 35

Canaliculi

Answer 35

channels lined by the cell membranes of adjacent hepatocytes Carry bile outward from hepatocytes → Portal Triad where they join a branch of the bile duct

Question 36

Zone 1 of the liver

Answer 36

nearest to distributing vessels first to be affected by incoming blood

Question 37

Zone 3 of the liver

Answer 37

furthest from vessels first to show ischaemic necrosis and fat accumulation last to be affected by toxic substances

Question 38

Zone 2 of the liver

Answer 38

mix of zone 1 & 3 characteristics

Question 39

Classical Liver Lobule

Answer 39

Hexagonal Division 1 central vein 6 hepatic portal triads one in each corner of the hexagon

Question 40

Portal Lobule

Answer 40

Triangular division 3 central veins in each corner 1 hepatic portal triad in the centre

Question 41

Hepatic Acinus

Answer 41

2 adjacent triangular wedges 2 central veins at each apex of each triangle 2 hepatic lobules

Question 42

Pancreatic acini cells

Answer 42

contain inactive forms of digestive enzymes drained by a series of inter-connecting ducts emptying directly into the main pancreatic duct