HISTOLOGY

Question 1

What are the principle cells in the liver

Answer 1

hepatocytes

Question 2

What comprises the portal triad

Answer 2

portal vein, heaptic artery, bile duct

Question 3

what is the definition of a lobule

Answer 3

area drained by 1 central hepatic venule

Question 4

describe the structure of a lobule

Answer 4

central vein in centre surrounded by radiating core of hepatocytes;
Corners - portal triad

Question 5

what is the difference between acinus and sinusoids

Answer 5

based around blood supply not drainage

Question 6

describe the structure of an acinus

Answer 6

diamond; portal triad on ends of short axis and central veins at corners

Question 7

where is glycogen removed from 1st in lobule

Answer 7

hepatocytes closer to centre

Question 8

what happens to hepatocytes at periphery of lobule

Answer 8

have higher glucose concentration so able to store glucose as glycogen

Question 9

describe the nuclei of hepatocytes

Answer 9

large, central, spherical

may be binucleate

Question 10

what are hepatocytes

Answer 10

principle functional cells of the liver

Question 11

what shape and type of cell are hepatocytes

Answer 11

polyheadral epithelial cells

Question 12

describe the cytoplasm of hepatocyes

Answer 12

granular nature due to abdundant mitochondria

Question 13

describe the nucleoli of hepatocytes and explain why

Answer 13

prominent because metabolically active

Question 14

what is the space of Disse

Answer 14

perisinusoidal space

contains reticulin fibres and stem cell populations

Question 15

what are sinusoids

Answer 15

highly specialised fenestrated vessels that carry mix of venous (70%) and arterial (30%) blood that bathes cords of liver cells

Question 16

describe the structure of sinusoids

Answer 16

thin discontinuous feensttaed epithelium with no basement membrane between vascular endothelial cells and hepatocytes

Question 17

what are Kupffer cells derived from

Answer 17

blood monocytes (like osteoclast in bones)

Question 18

hepatocyte ultrastructure

Answer 18

arranged in cords with intervening sinusoids

Question 19

surfaces of hepatocytes

Answer 19

sinusoidal, canalicular, intercellular

Question 20

describe the purpose sinusoidal surface of hepatocytes

Answer 20

70%
permits exchange of material with blood
Has space of disse

Question 21

what does the space of disse do

Answer 21

secrete serum albumin and fibrinogen (synthessied by liver)

Question 22

what do Ito cells do

Answer 22

store fat

Question 23

describe the purpose of canalicular surface of hepatocytes

Answer 23

15%
permits exchange of bile into bile ducts
between hepatocytes and bile canaliculs

Question 24

describe intercellular surface of hepatocytes

Answer 24

5%

between 1 hepatocytes and the next

Question 25

how do hepatocytes appear in electron microscopy

Answer 25

``` large nucleus (>2n) prominent nucleus Active Golgi apparatus Prominent ER lots of mitochondria Numerous peroxisomes ```

Question 26

what do hepatocytes do

Answer 26

synthesis bile

Question 27

describe the pathway of bile ultrastructurally

Answer 27

canaliculi to bile ductules which fuse to form trabecular ducts which fuse to form bile ducts

Question 28

bile canaliculi definition

Answer 28

extra-cellular channels between hepatocytes into which hepatocytes secrete bile

Question 29

describe the epithelium of bile ducts

Answer 29

simple cuboidal to columnar epithelium on basement membrane

Question 30

How is energy stored in hepatocyes

Answer 30

in form of glycogen which forms rosettes in cytoplasm

Question 31

how does blood come from spleen to liver

Answer 31

via splenic branch of hepatic portal vein

Question 32

what does blood in the splenic branch of hepatic portal vein have in it

Answer 32

iron from ferritin

Question 33

what is ferritin

Answer 33

protein with iron core

Question 34

where is ferritin discharged and picked up from

Answer 34

discharged by spleen | picked up by Kupffer cells in liver

Question 35

what is the purpose of the gall bladder

Answer 35

concentrates and stores bile

Question 36

how does the gall bladder expel bile

Answer 36

via common bile duct into duodenum

Question 37

where is CCK produced and why

Answer 37

by endocrine cells in duodenal walls in response to fat entering duodenum from stomach

Question 38

what nerves innervated pancrease (secretor-motor fibres)

Answer 38

vagus nerve

Question 39

epithelium of gall bladder

Answer 39

simple columnar epithelium resting on basement membrane

Question 40

layers of gall bladder

Answer 40

``` simple columnar epithelium on basement membrane Specilaised mucosa Smooth muscle = muscularis propria NO MUSCULARIS MUCOSAE adventitia ```

Question 41

describe the mucosa of the gall bladder

Answer 41

microvilli thrown into folds - adapted for water and salt absorption

Question 42

what is the purpose of the exocrine pancrreas

Answer 42

- Synthesise and secrete enzymes and bicarbonate rich fluid into duodenum

Question 43

what surrounds the exocrine pancreas

Answer 43

poorly defined fibrous capsules with septa dividing the gland into lobules

Question 44

what slightly surprising thing is found in the exocrine pancreas

Answer 44

Pacinian corpuscles

Question 45

what sort of organe is the exocrine pancrease

Answer 45

epithelial

Question 46

how are epithelial cells in the exocrine pancreas arranged

Answer 46

in acini; pyramidal shaped, basally rich in RER, each cell has single nucleus, prominent zymogen granules apically

Question 47

what colour does RER stain haemotoxylin

Answer 47

blue

Question 48

describe the structure of the exocrine pancreas

Answer 48

comprise acini with pyramidal cells and zymogen granules and specialised duct system that secrete bicarbonate rich fluid

Question 49

where do secretions from the exocrine pancreas drain

Answer 49

into duct system

Question 50

describe the pathway of pancreatic ducts

Answer 50

Centroacinar cells (bicarbonate rich alkaline solution) go to Intercalated ducts which go to Interlobular ducts (lined by cuboidal to low columnar cells) which go to Main pancreatic duct