Liver structure and function

Question 1

how many lobes does the liver have and what are they?

Answer 1

2 major - right and left

2 minor - caudate and quadrate

Question 2

where do the vessels and nerves enter the liver?

Answer 2

at the porta which is on the inferior surface

Question 3

what all enters the liver at the porta?

Answer 3

blood vessels - hepatic artery and hepatic portal vein
ducts - right/left hepatic ducts –> common hepatic duct)
lymphatic vessels
nerves - hepatic nerve plexus

Question 4

the common hepatic duct joins which duct from the gallbladder?

Answer 4

cystic duct

Question 5

what is at the junction of the common bile duct and pancreatic duct?

Answer 5

sphincter of Oddi

major duodenal papilla

Question 6

what is the name of the ligament which within the liver and separates the right from the left lobe?

Answer 6

falciform ligament

Question 7

how is the liver peritonised?

Answer 7

intraperitoneal

Question 8

where is the bare area of the liver located and what is it surrounded by?

Answer 8

the diaphragmatic surface

covered by coronary ligament

Question 9

at the porta, what is the function of the connective tissue capsule ?

Answer 9

the connective tissue capsule branches throughout the liver forming a network of septa (wall) to provide support

Question 10

what is involved in the portal triad and where is it located?

Answer 10

hepatic artery, vein and duct

located at the corner of each hexagonal lobe

Question 11

where are the central veins located in the liver?

Answer 11

the centre of each lobe

Question 12

describe the structure of the central veins in the liver.

Answer 12

hepatic cords radiate out from the central veins
cords are composed of hepatocytes
between the cells lie bile canaliculus
the gaps between each hepatic cord are fenestrated blood vessels called sinusoids

Question 13

what are the 6 components of bile?

Answer 13

bile acids
lecithin
cholesterol
(top 3 solubilise fat and are synthesised in the liver)
bile pigments (bilirubin from haemoglobin)
toxic metals (detoxification in the liver)
bicarbonate for neutralisation

Question 14

what are the 5 components of bile secreted from?

bicarbonate is secreted from duct cells

Answer 14

hepatocytes

Question 15

what are bile pigments?

Answer 15

breakdown products of haemoglobin from old/damaged RBC (erythrocytes)

Question 16

what makes bile yellow?

Answer 16

bilirubin from erythrocytes is extracted from the blood by hepatocytes and secreted in bile

Question 17

what makes faeces brown?

Answer 17

bilirubin is modified by bacterial enzymes making brown pigments

Question 18

what makes urine yellow?

Answer 18

reabsorbed bilirubin from the intestine causes it to be extracted in our urine

Question 19

what are bile acids synthesised in our liver from?

Answer 19

cholesterol

Question 20

before bile acids can be secreted what happens and why?

Answer 20

binds with glycine or taurine to increase solubility

Question 21

secreted bile salts are recycled via what circulation?

Answer 21

the enterohepatic circulation

Question 22

what is the difference between bile acids and bile salts?

Answer 22

bile acids is produced from the liver but bile salts are bile acids + glycine or taurine because it cannot be excreted as bile acid as it is insoluble

Question 23

the gallbladder only has 3 layers, what are these?

Answer 23

mucosa
muscularis
serosa

Question 24

what is the main controller of bile secretion into the duodenum?

Answer 24

sphincter of oddi

Question 25

by how many times does the gallbladder concentrate bile?

Answer 25

5-20 times

Question 26

fat in the duodenum causes the release of what?

Answer 26

CCK

Question 27

when CCK is released what happens?

Answer 27

the sphincter of Oddi relaxes and the gallbladder contracts (releasing bile)

Question 28

what does CCK control?

Answer 28

pancreatic enzyme and bile secretion

Question 29

what triggers the secretion of secretin?

Answer 29

acid in the duodenum

Question 30

what affects does secretin have?

Answer 30

decreases acid secretion
decreases gastric emptying
increase duodenal, pancreatic and bile duct HC03 secretion
= neutralisation

Question 31

what affects does CCK have?

Answer 31

decreases gastric emptying
increases pancreatic enzyme secretion from acing cells
gallbladder contraction
relaxation of sphincter of oddi
= digestion