118 - Liver and Pancreas Histology

Question 1

Functions of the liver 1 2 3 4 5 6 7 8 9 10 11 12

Answer 1

1) Major glycogen store 2) Gluconeogenesis 3) Cholesterol synthesis 4) Lipoprotein synthesis 5) Ketone body synthesis 6) Production of all blood proteins except antibodies 7) Makes all non-essential amino acids 8) Detoxifies metabolic wastes 9) Iron storage for haemoglobin 10) Destroys hormones 11) Destroys toxins 12) Bile production

Question 2

Gluconeogenesis

Answer 2

Breakdown of lactic acid, amino acids, glycerol to glucose

Question 3

Example of a metabolic waste detoxified by the liver

Answer 3

Ammonia. Converted to urea by the liver.

Question 4

Shape of hepatocytes

Answer 4

Polyhedral (six surfaces). Around 25micrometers across

Question 5

Internal structure of hepatocytes 1 2 3 4

Answer 5

1) One or two nuclei. Many cells are tetraploid or polyploid 2) Prominent rough ER, Golgi complexes, vesicles for protein synthesis, transport 3) Prominent smooth ER for fat metabolism 4) Many mitochondria

Question 6

Which cell type are hepatocytes?

Answer 6

Epithelial

Question 7

Hepatocyte lifespan

Answer 7

~150 days

Question 8

Replacement of hepatocytes

Answer 8

Replaced by divisions of existing hepatocytes

Question 9

Percentage of liver weight that is hepatocyte

Answer 9

75%

Question 10

Organisation of hepatocytes in the liver

Answer 10

Organised around blood vessels

Question 11

Name for thin capsule around liver, blood vessels and ducts

Answer 11

Glisson’s capsule

Question 12

Connective tissue in the liver 1 2

Answer 12

1) Glisson’s capsule (around liver, blood vessels and ducts) 2) Hepatocytes are supported by reticular fibres (type III collagen)

Question 13

Organisational units of hepatocytes

Answer 13

Lobules

Question 14

Liver lobules

Answer 14

Stacks of hepatocytes in plates. ~0.7x2mm in size Kinda hexagonal crystal shape

Question 15

Blood vessels associated with a lobule

Answer 15

Central vein runs through middle Portal triads on edges

Question 16

Portal triads 1 2 3 4

Answer 16

1) Two blood vessels and a duct 2) A branch of the hepatic portal vein (blood from gut) 3) Branch of hepatic artery (to oxygenate blood) 4) Supplies multiple lobules

Question 17

How do portal triads and central vein interact?

Answer 17

Vein and artery in portal triads give rise to sinusoids, which flow into the middle of the lobule, into the central vein.

Question 18

Sinusoids

Answer 18

Network of branches from portal triads (on the exterior of lobules) to the central vein of a lobule.

Question 19

Type of blood carried by sinusoids

Answer 19

Mixed oxygenated (20%) and deoxygenated (80%)

Question 20

Central vein role

Answer 20

Carry blood from sinusoids to hepatic vein and out of liver

Question 21

Arrangement of sinusoids in lobule

Answer 21

Each plate of hepatocytes has a sinusoid above and below it

Question 22

Name for space around hepatocytes that bathes them in plasma

Answer 22

Space of Disse

Question 23

How are hepatocytes exposed to blood contents?

Answer 23

Sinusoids run above and below each plate of lobules. Sinusoids have incomplete walls. Space of Disse around hepatocytes is full of plasma from sinusoids

Question 24

*Histological slide of heatocyte in situ

Answer 24

Question 25

How do hepatocytes increase surface area?

Answer 25

Microvilli

Question 26

Two arrangements of vessels in lobules

Answer 26

1) Classical lobule 2) Hepatic lobule

Question 27

Hepatic lobule

Answer 27

Hepatic and portal vein in middle of lobule. Emphasises metabolic organisation

Question 28

\*Hepatic lobule vs classical lobule

Answer 28

Question 29

Zone 1 of hepatic acinus

Answer 29

High in O2, high in toxins, high in nutrients

Question 30

Zone 3 of hepatic acinus

Answer 30

Low in O2, low in toxins, low in metabolites

Question 31

\*Schematic of a hepatic acinus

Answer 31

Question 32

Hepatic acinus 1 2 3

Answer 32

1) The functional unit of the liver 2) Arranged into zones based on proximity to arterial blood supply: zone1 is closest, zone 3 is furthest 3) Arrangement of classical lobules

Question 33

\*Schematic showing difference between portal and hepatic lobules

Answer 33

Portal lobules are in solid lines, hepatic are in dotted lines

Question 34

What produce bile salts?

Answer 34

Hepatocytes

Question 35

Which product do hepatocytes synthesise bile salts from?

Answer 35

Cholesterol

Question 36

Why is bile green?

Answer 36

Bile pigments are green. Bile pigments are breakdown products of haemoglobin, from destruction of RBCs in the spleen and liver

Question 37

How is bile released from hepatocytes and liver?

Answer 37

Bile produced by hepatocytes is released into channels between hepatocytes (cannaliculi), which flows outwards into bile ducts in the portal triads

Question 38

Histological appearance of gall bladder 1 2 3

Answer 38

1) Smooth muscle forms muscular sac 2) Simple columnar epithelium 3) Tough serosa

Question 39

Functions of gall bladder 1 2

Answer 39

1) Concentration of bile salts 2) Storage of bile

Question 40

How does the gall bladder concentrate bile salts?

Answer 40

About 90% of bile is resorbed by gall bladder, concentrating bile salts and pigments.

Question 41

Name for sphincter that diverts bile to gall bladder for storage

Answer 41

Sphincter of Oddi

Question 42

Gall stones

Answer 42

Precipitates of bile salts and/or cholesterol

Question 43

Hormonal control of gall bladder 1 2 3

Answer 43

1) Fat in duodenum stimulates specialised cells of duodenal mucosa to release cholecystokinin into blood 2) CCK causes relaxation of sphincter of Oddi, contraction of gall bladder. 3) Bile squirts into the duodenum

Question 44

Duct that sphincter of Oddi controls

Answer 44

Common bile duct

Question 45

Functions of pancreas 1 2

Answer 45

1) Enzyme release 2) Bicarbonate release

Question 46

Components of pancreastic juice

Answer 46

Proteases, lipases, amylases, nucleases and bicarbonate ions

Question 47

Histological appearance of pancreas

Answer 47

Islets of Langerhans. Pancreatic acini

Question 48

What forms pancreatic glands

Answer 48

Pancreatic acini. Balls of cells with duct in the middle

Question 49

What type of enzymes does the pancreas release?

Answer 49

Zymogens