Liver structure, function and pathologies

Question 1

What percentage of body weight is the liver

Answer 1

2-3%

Question 2

What are the lobes of the liver

Answer 2

Major lobes: Right>left
minor lobes: caudate, quadrate

Question 3

What joins the right and left lobe anteriorly and posteriorly

Answer 3

Falciform ligament–> anterior, lesser omentum: posteriorly

Question 4

What makes up the Porta

Answer 4

Hepatic artery, portal vein and hepatic duct

Question 5

What are the categories of cells in the liver

Answer 5

Parenchymal, non-parenchymal cells, Cholingiocytes

Question 6

what are parenchymal cells

Answer 6

Hepatocytes: polarised (2 membranes), basolateral membrane face sinusoidal epithelium cells of capillaries.

Question 7

What are cholangiocytes

Answer 7

biliary epithelial cells. Bile canaliculi passage way of bile from hepatocytes to bile duct.

Question 8

Liver blood supplies

Answer 8

Portal blood: portal vein, high in nutrients low in oxygen.
Hepatic artery: high oxygen, low nutrients

Question 9

Blood pathway into and out of liver

Answer 9

Hepatic artery + portal vein -> central vein–>hepatic vein –> IVC

Question 10

What is the functional unit of the liver?

Answer 10

Hepatic lobule. Hexagonal shape with portal triad on each corner.

Question 11

What makes up the portal triad

Answer 11

Portal vein, hepatic artery, bile duct and nerves and lymph vessels

Question 12

what connects the portal triad to the central vein

Answer 12

hepatocyte cords made of hepatocytes, with sinusoids surrounding them and bile canaliculus between cells.

Question 13

Direction of flow of bile and blood in hepatic lobule

Answer 13

bile moves from the centre outwards, and blood moves from outside towards the central vein.

Question 14

Bile constituents

Answer 14

Bile acids, lecithin, cholesterol, bilirubin, toxic metals and bicarbonate

Question 15

what bile constituents solubilize fat?

Answer 15

Bile acids, lecithin and cholesterol

Question 16

Where are all the bile constituents secreted?

Answer 16

All are secreted in the liver except bicarbonate which is secreted from duct cells.

Question 17

Function of bicarbonate

Answer 17

Neutralisation of acid chyme

Question 18

What is the bile pigment

Answer 18

Bilirubin

Question 19

How is bilirubin formed

Answer 19

breakdown of haemoglobin from old/damaged erythrocytes

Question 20

Pathway of bile after breakdown and colour

Answer 20

secreted into bile from blood=yellow bile, bile–>intestines: bilirubin then modified by bacteria in the intestines=brown faeces. reabsorbed bilirubin excreted in urine=yellow urine.

Question 21

What is the enterohepatic circulation

Answer 21

“bile’s journey”
liver–>bile duct–>duodenum–>ileum–>hepatic portal vein–> liver

Question 22

How much bile salts are produced each day

Answer 22

0.5g/day and 95% of bile salts/acids are reabsorbed

Question 23

what are conjugated bile salts

Answer 23

bile acids that have bound to taurine, glycine or sulphate in the liver before passing through the bile duct. this increases water solubility.

Question 24

what happens to bile salts in the intestines

Answer 24

bacteria degrades the bile salts (–>acids), and they become less hydrophilic and are reabsorbed into the blood

Question 25

Layers in the gall bladder

Answer 25

Mucosa (folded, rugae: allows for expansion), muscularis (smooth muscle=contraction), serosa (CT)

Question 26

What controls Bile secretion?

Answer 26

Sphincter of Oddi, CCK relaxes the sphincter.

Question 27

How does bile become concentrated in the gall bladder?

Answer 27

Na+ is removed via a sodium channel on the epithelium and the change in osmolarity allows water to move by para transportation across membrane. Na/K pump ensures negative conc. of Na in the epithelial cell.

Question 28

What causes the secretion of CCK

Answer 28

Fat in the duodenum. Bile secreted into duodenum –> fat solubilastion

Question 29

What is released when there is acid in the duodenum

Answer 29

Secretin, increases bicarbonate secretion neutralising the acid.

Question 30

What happens when secretin is released

Answer 30

decrease in gastric emptying and acid secretion. increased in bicarbonate secretion in pancreas, bile duct and duodenum.

Question 31

what occurs when Cholecystokinin is released

Answer 31

decreased gastric emptying, increase pancreas enzyme secretion. Gallbladder contracts and sphincter of oddi relaxes.