Liver structure and function

Question 1

where is the liver located in the body

Answer 1

upper right quadrant of abdomen (tucked against inferior surface of diaphragm)

Question 2

name the major and minor lobes

Answer 2

major - left and right

minor - caudate and quadrate

Question 3

what is the porta

Answer 3

the single entry exit point for all vessels, ducts and nerves to the liver - found on the inferior surface

Question 4

liver blood supply

Answer 4

hepatic portal vein, hepatic artery

Question 5

liver lymphatic vessels and ducts

Answer 5

hepatic lymphs, left/right hepatic ducts join to form the common hepatic duct

Question 6

liver nerve supply

Answer 6

hepatic nerve plexus

Question 7

talk through the route from the common hepatic duct to the duodenum

Answer 7

1. comon hepatic duct joined by cystic duct from gallbladder
2. join to form the common bile duct
3. common bile duct joins with the pancreatic duct
4. travel to the major duodenal papilla (sphincter of Oddi)
5. enter into duodenum

Question 8

what is the liver covered by

Answer 8

a connective tissue capsule and visceral peritoneum except for the bare area

Question 9

what is the bare area of the liver

Answer 9

small area on the diaphragmatic surface surrounded by the coronary ligament - not covered in the capsule

Question 10

what is the septa

Answer 10

a branching network of connective tissue that goes into the body of the liver for support - divided the liver into hexagonal lobules

Question 11

what comprises the portal triad

Answer 11

hepatic portal vein, hepatic artery, hepatic duct

Question 12

where is the portal triad located

Answer 12

at each corner of a hexagonal lobule

Question 13

what is found at the centre of each lobule

Answer 13

hepatic veins that go to the IVC

Question 14

what are hepatic cords

Answer 14

composed of hepatocytes (functional liver cells) they radiate out from central veins (like wheel spoke)

Question 15

what lie between the hepatic cords

Answer 15

hepatic sinusoids - blood channels

Question 16

what is the bile canaliculus and where does it lie

Answer 16

it is a cleft like lumen that lies between cells within each hepatic cord

Question 17

what are the role of hepatocytes

Answer 17

1. bile synthesis
2. nutrient storage (glycogen, fat, vits (B12, A, D, E, K) Cu, Fe)
3. nutrient interconversion
4. detoxification

Question 18

what is the path venous blood takes through the liver

Answer 18

1. O2 depleted/nutrient rich blood in through Hepatic portal vein
2. through hepatic sinusoids
3. to central veins
4. to hepatic veins

Question 19

what is the path arterial blood takes through the liver

Answer 19

1. O2 rich/nutrient depleted blood in through Hepatic artery
2. through hepatic sinusoids
3. to central veins
4. to hepatic veins

Question 20

what is the path taken by bile through the liver

Answer 20

1. continuously going between hepatic sinusoids and hepatocytes
2. from hepatocytes travel to cannaliculi
3. travel to hepatic ducts

Question 21

What is the alimentary role of the liver

Answer 21

production and secretion of bile

Question 22

what are the six components of bile and where are they secreted from

Answer 22

1. bile acid
2. lecithin
3. cholesterol
4. bile pigments
5. toxic metals
6. bicarbonate

1-5 secreted by hepatocytes

6 secreted by duct cells

Question 23

what is the role of bile acids, lecithin and cholesterol

Answer 23

synthesised in the liver to solibulise fat

Question 24

what is the role of bicarbonate

Answer 24

neutralisation of acid chyme

Question 25

what are bile pigments made from

Answer 25

bilirubin - breakdown product of haemoglobin form old/damaged erythrocytes

Question 26

How does bilirubin cause yellow bile

Answer 26

extracted from blood by hepatocytes and secreted into bile

Question 27

How does bilirubin cause brown faeces

Answer 27

modified by bacterial enzymes = brown pigments

Question 28

How does bilirubin cause yellow urine

Answer 28

reabsorbed and excreted in urine

Question 29

what are bile acids synthesised from

Answer 29

synthesised from cholesterol in the liver

Question 30

what happens to bile acids before secretion

Answer 30

conjugated with glycine or taurine to increase solubility - create bile salts

Question 31

secreted bile salts are recycled via what circulation

Answer 31

enterohepatic

Question 32

list the enterohepatic circulatory route

Answer 32

1. liver
2. bile duct
3. duodenum
4. ileum
5. hepatic portal vein
6. liver etc

Question 33

where is the gallbladder found

Answer 33

it is a sac like structure on the inferior surface of the liver

Question 34

what are the three wall layers

Answer 34

1. mucosa (folded - rugae - for expansion
2. muscularis (smooth muscle - for contraction)
3. Serosa - connective tissue

Question 35

what does the gallbladder go into

Answer 35

the cystic duct - common bile duct

Question 36

what controls bile secretion

Answer 36

the sphincter of Oddi controls release of bile and pancreatic juice into duodenum - When contracted (closed) bile forced back into gallbladder

Question 37

how does the gallbladder concentrate bile

Answer 37

through the absorption of Na+ and H20 - bile is concentrated 5-20 times

Question 38

what controls the sphincter of Oddi

Answer 38

fat in the duodenum releases CCK

1. causes sphincter of Oddi to relax
2. casues gallbladde to contract

Question 39

summarise how secretin cases neutralisation

Answer 39

1.Acid in duodenum
2. causes release of Secretin
3. Gastric acid secretion decreases
4. Gastric emptying decreases
5. Duodenal HCO3 secretion increases
6. Pancreatic HCO3 secretion increases
7. Bile duct HCO3 secretion increases

Question 40

summarise how cholecysrokinin (CCK) causes digestion

Answer 40

1. Fat/amino acids in duodenum
2. causes release of CCK
3. Gastric emptying decreases
4. Pancreatic enzyme secretion increases
5. Gallbladder contraction occurs
6. Relaxation of Sphincter of Oddi