Liver in Health

Question 1

Describe the boundaries of the liver

Answer 1

Between diaphragm cranial, stomach & intestines caudally

Question 2

Where does the bulk of the liver lie?

Answer 2

on the RHS of the cranial abdominal cavity, some is beyond ribcage on LHS in dog

Question 3

How is liver attached to surrounding structures?

Answer 3

Closely attached to diaphragm, caecum and right kidney via ligaments + pressure of viscera

Question 4

Describe the canine liver

Answer 4

Deeply lobulated.
R:L = 3:2
Almost entire costa
Has gall bladder

Question 5

Describe the pig liver

Answer 5

Speckled surface
Gall bladder (single duct)

Question 6

Describe the positioning of the avian liver

Answer 6

Do diaphragm so liver wraps around heart

Gall bladder

Question 7

Describe the equine liver

Answer 7

Smaller, lobes less distinct

long axis oblique (right lobe dorsal to left lobe)

Question 8

How many lobes does the equine liver have?

Answer 8

Left/ quadrate/ right/ caudate

Question 9

Describe bile path in horse

Answer 9

No gall bladder- bile duct opens at major duodenal papilla in conjunction with pancreatic duct

Question 10

Describe liver in cow

Answer 10

Rotated 90deg, virtually all on RHS, largely covered by lung
Elongated gall bladder, bile duct opens without pancreatic duct

Question 11

Where might the bovine liver be palpated?

Answer 11

Cranial right paralumbar fossa

Question 12

Describe the dorsal and ventral borders of the liver

Answer 12

Dorsal –> midline groove for vena cava, LHS notch for oesophagus
Ventral –> Sharp edges, notch for kidney

Question 13

Name the lobes of the liver

Answer 13

L Lateral, L medial, Quadrate, R lateral, R medial, Caudate

Question 14

Where is gall bladder found?

Answer 14

Quadrate lobe

Question 15

Which connecting peritoneum originates from the liver?

Answer 15

Lesser omentum

Question 16

What are the functions of the liver?

Answer 16

Bile production
Protein/ carbohydrate/ fat metabolism role (drains blood from GIT)
Detoxification/ biotransformation/ synthesis/ storage/ phagocytosis

Question 17

What are the processes of the caudate lobe?

Answer 17

Papillary and caudate processes

Question 18

What are the ligaments of the liver?

Answer 18

R, L triangular
Coronary
Falciform
Lesser omentum

Question 19

Describe the attachment properties of the coronary ligament

Answer 19

Ligament surrounds caudal vena cava on cranial aspect, attaches strongly to diaphragm

Question 20

Describe the importance of the hepatic artery to the liver

Answer 20

Supply oxygenated blood,

Question 21

Describe the importance of the hepatic artery to the liver

Answer 21

Supply most oxygenated blood, 20%

Question 22

Describe how blood is collected from the liver

Answer 22

Single set of veins –> open into caudal vena cava

Question 23

Describe properties of L R triangular ligaments

Answer 23

Attach liver to diaphragm at site of veins

Question 24

Describe properties of falciform ligament

Answer 24

Attaches L R medial lobes of liver, and liver to ventral body wall

Question 25

Describe properties of round ligament

Answer 25

Vestigial umbilical vein, free margin of falciform ligament

Question 26

Where is the gall bladder found?

Answer 26

Between quadrate and right medial lobes

Question 27

Describe the bile duct system

Answer 27

Microscopic canaliculi between hepatic veins --> ductules --> common hepatic duct leaves portal area --> opens at duodenum

Question 28

Which nervous systems innervate the liver?

Answer 28

Sympathetic & parasympathetic

Question 29

Describe importance of portal vein to liver

Answer 29

Supplies 4/5 total BV

Question 30

Where does blood from liver drain?

Answer 30

Caudal vena cava

Question 31

Describe the liver parenchyma

Answer 31

Red/ brown, friable, covered by serosa and tunica fibrous, uniform histology

Question 32

What cells make up the liver?

Answer 32

Hepatocytes Endothelial cells Kupffer cells

Question 33

How are hepatocytes arranged?

Answer 33

In cords, with tight junctions b/w

Question 34

What is present between hepatocyte tight junctions?

Answer 34

Bile canaliculi

Question 35

What is the action of kupffer cells?

Answer 35

Phagocytosis --> engulf debris & old RBC

Question 36

Where are Kupffer cells found?

Answer 36

Lining sinusoids

Question 37

What is the basic structural unit of the liver parenchyma?

Answer 37

Classical lobule

Question 38

Define a classical lobule

Answer 38

Hexagonal structure ... - Central vein at centre - Portal triads at periphery

Question 39

Define a portal triad

Answer 39

Portal vein/ hepatic artery/ bile duct

Question 40

Describe the path of cords of hepatocytes

Answer 40

Radiate from central vein so blood flows centripedally

Question 41

What is a portal lobule?

Answer 41

The functional secretory unit that drains bile, triangular

Question 42

What are the boundaries of a portal lobule?

Answer 42

Points of triangle are 3 central veins of adjacent classical lobules so bile duct is central axis

Question 43

What is a liver acinus?

Answer 43

The functional unit of blood supply to hepatocytes, diamond

Question 44

What are the boundaries of the liver acinus?

Answer 44

Draw lines via 2 adjacent central veins via portal triads

Question 45

How is the liver acinus divided?

Answer 45

Zone 1 --> centre of triangle, most blood supply | Zone 3 --> bordering central vein

Question 46

What are bile ducts lined by?

Answer 46

cuboidal-columnar epithelium

Question 47

What is the function of the gall bladder?

Answer 47

Store and concentrate bile

Question 48

Which hormone promotes bile secretion?

Answer 48

Cholicystokinin

Question 49

Where are RBC produced?

Answer 49

Liver, bone marrow, spleen

Question 50

An increase in what causes jaundice?

Answer 50

Bilirubin in circulating blood

Question 51

What do hepatocytes to do bilirubin?

Answer 51

make water soluble

Question 52

Describe how liver makes bile (start with hepatocytes)

Answer 52

-Cholesterol --> bile acids --> bind to albumin to form bile salts -Bile salts + bilirubin (made from heme breakdown) + bicarbonate (secreted from duct cells) + lecithin = bile!!!

Question 53

What is enterohepatic recirculation?

Answer 53

95% bile acids delivered to duodenum absorbed back into blood within ileum, rest is lost in urine/faeces

Question 54

Which hormones stimulate secretion of bile?

Answer 54

Cholecystokinin & secretin

Question 55

What stimulates release of cholecystokinin?

Answer 55

Fat in duodenum

Question 56

What is the action of cholecystokinin?

Answer 56

contraction of gall bladder & common bile duct

Question 57

What stimulates secretion of secretin?

Answer 57

acid in the duodenum

Question 58

What is the effect of secretin?

Answer 58

Stimulates biliary duct cells to secrete bicarbonate & water, --> inc volume bile --> inc flow out into intestine (similar action to in pancreas!)

Question 59

Which cells synthesise bile?

Answer 59

Hepatocytes

Question 60

What is bile made from?

Answer 60

cholesterol (bile acids) --> bind to albumin = bile salts | + bicarbonate + bilirubin (RBC breakdown) + lecithin

Question 61

Describe gluconeogenesis

Answer 61

hepatocytes mobilise glucose from non-carbohydrate sources

Question 62

What is a function of hepatocytes important for RBC?

Answer 62

haematopoiesis

Question 63

Which proteins are synthesised in the liver?

Answer 63

Albumin Clotting factors Anti-clotting factors

Question 64

What is the role of hepatocytes in relation to ammonia?

Answer 64

Convert ammonia to water soluble urea (from GIT flora)

Question 65

What is the role of Kupffer cells?

Answer 65

Phagocytosis

Question 66

Which vessel provides liver of most of its blood supply?

Answer 66

Portal vein

Question 67

Describe the portal triad

Answer 67

Portal vein + hepatic artery + bile ducts + lymphatics

Question 68

Which direction does blood flow in classical lobule?

Answer 68

From lobule periphery to central vein --> most hepatic arteries empty into peribiliary plexus in portal areas before feeding into sinusoids

Question 69

Describe the Rappoport model's "Zone 1" area

Answer 69

Periportal area --> highest O2, most mitotic division

Question 70

Describe the Rappoport model's "Zone 2" area

Answer 70

Intermediate area (no one really cares) --> affected during evens of blue green algae toxicity

Question 71

Describe the Rappoport model's "Zone 3" area

Answer 71

Oldest, closest to central vein, important in metabolising drugs/ toxins/ hormones, susceptible to hypoxia

Question 72

What are the role of sinusoids in the liver?

Answer 72

fenestrated BV to promote exchange of macromolecules between hepatocytes & blood

Question 73

Which cells are located within sinusoids?

Answer 73

Kupffer cells

Question 74

Perisinusoidal space is the site of __ formation

Answer 74

Hepatic lymph formation

Question 75

Where are stellate cells found?

Answer 75

between sinusoidal endothelial cells and hepatocytes

Question 76

What are the role of stellate cells?

Answer 76

Divide mitotically during inflammation/ necrosis and deposit collagen into perisinusoidal space --> progressive fibrosis

Question 77

What is the cause of liver cirrhosis?

Answer 77

Progressive fibrosis of hepatic parenchyma

Question 78

During hepatic regeneration, what are some sources of hepatocytes?

Answer 78

``` Hepatocytes (mitotic division) Oval cells (bile ductal precursor cells) that can also become hepatocytes as a backup ```

Question 79

What causes jaundice??

Answer 79

Excessive bilirubin (conjugated/ unconjugated) in blood stream

Question 80

Why is it not viable to assume jaundice = liver failure/ disease?

Answer 80

Because jaundice can also result from intravascular haemolytic anaemia/ cholestasis/ (& liver Dx)

Question 81

Which part of the normal process of bilirubin metabolism is most vulnerable to disruption and why?

Answer 81

hepatocytes moving bile to cannaliculi b/c requires a lot of energy! (to move bile to a place where bile conc is already v high)