Liver Structure and Function

Question 1

What is the largest organ in the body?

Answer 1

The liver which weights about 1.4kg

Question 2

Where is the liver located within the abdomen?

Answer 2

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

Question 3

How many lobes does the liver contain?

Answer 3

4

Question 4

What are the 4 lobes of the liver?

Answer 4

Left lobe

Right lobe

Caudate lobe

Quadrate lobe

Question 5

On what surface is the portal of the liver?

Answer 5

Posterior

Question 6

Whats enters and exits the liver through the porta?

Answer 6

Blood vessels (hepatic portal vein, hepatic artery)

Lymphatic vessels

Ducts (right/left hepatic ducts forming common hepatic duct)

Nerves (hepatic nerve plexus)

Question 7

Explain the anastomosis of the common hepatic duct to reach the spincter of Oddi?

Answer 7

Common hepatic duct joined by cystic duct to form common bile duct

Common bile duct joined by pancreatic duct to form major duodenal papilla

Question 8

What does the coronary ligament attach the liver to?

Answer 8

Inferior surface of diaphragm

Question 9

What is the liver covered by?

Answer 9

Connective tissue capsule and visceral peritoneum (except for bare area)

Question 10

Where is the bare area of the liver?

Answer 10

Diaphragmatic surface surrounded by coronary ligament

Question 11

What does the connective tissue surrounding the liver become at the porta?

Answer 11

Branching network of septa into the body of the liver to give support

Question 12

What doe vessels, ducts and nerves follow throughout the liver?

Answer 12

Septa

Question 13

What does the septa divide the liver into?

Answer 13

Hexagonal lobules

Question 14

What forms the portal triad?

Answer 14

Hepatic portal vein, hepatic artery and hepatic duct

Question 15

Where are portal triads found?

Answer 15

At each corner of hexagonal lobule (also with nerves and lymph vessels)

Question 16

What is at the centre of each lobule?

Answer 16

Central veins

Question 17

What do central veins of lobules go onto become?

Answer 17

Hepatic veins then inferior vena cava

Question 18

Explain the surroundings of central veins of lobules?

Answer 18

Hepatic cords radiate out of central veins

Cords composed of hepatocytes

Bile canaliculus lies between cells and within each cord

Spaces between hepatic cords are called hepatic sinusoids

Question 19

What are hepatic cords that radiate from central vein composed of?

Answer 19

Hepatocytes

Question 20

What are spaces between hepatic cords called?

Answer 20

Hepatic sinusoids

Question 21

What are hepatic sinusoids?

Answer 21

Blood channels

Question 22

What is the direction of blood and bile from the central vein of lobules?

Answer 22

Blood travels towards the central vein

Bile travels away from the central vein

Question 23

What kind of blood is made once the hepatic artery and hepatic portal vein mix together?

Answer 23

Blood high with oxygen and nutrient content

Question 24

Why is glucose stored in the liver as glycogen?

Answer 24

Glucose would be a problem osmotically

Question 25

What is the alimentary role of the liver?

Answer 25

Produce and secrete bile

Question 26

What does the hepatic artery form before entering hepatic sinusoids then the central veins?

Answer 26

Hepatic portal vein

Question 27

What would we not be able to do without bile?

Answer 27

Digest fats

Question 28

What are the 6 components of bile?

Answer 28

Bile acids Lecithin Cholesterol Bile pigments Toxic metals Bicarbonate

Question 29

Which of the 6 components of bile are not synthesised in the liver?

Answer 29

Toxic metals Bicarbonate

Question 30

What are bile pigments broken down from?

Answer 30

Haemoglobin from old/damaged erythrocytes

Question 31

What are the different kinds of bile pigments?

Answer 31

Bilirubin extracted from blood by hepatocytes (yellow) Bilirubin modified by bacterial enzymes (brown) Bilirubin reabsorbed from excreted urine (yellow)

Question 32

What are bile salts synthesised in the liver from?

Answer 32

Cholesterol

Question 33

How much bile salt is produced per day?

Answer 33

0.5g

Question 34

How much bile salt do we have in our bodies at one time?

Answer 34

10g

Question 35

Why is 0.5g of bile salt synthesised everyday?

Answer 35

We lose 0.5g in our faeces and 9.5g is recycled

Question 36

What happens to bile acids before secretion?

Answer 36

Conjugate with glycine or taurine to form bile salts

Question 37

Why do bile acids conjugate with glycine or taurin to form bile salts before secretion?

Answer 37

Increases solubility

Question 38

How are excreted bile salts recycled?

Answer 38

Via enterohepatic circulation: liver -\> bile duct -\> gallbladder -\> bileduct (returns) -\> duodenum -\> ileum -\> hepatic portal vein -\> liver etc

Question 39

What is the size of the gallbladder?

Answer 39

8cm wide x 4cm long

Question 40

Where is the gallbladder found?

Answer 40

Inferior surface of liver

Question 41

What is the function of the gallbladder?

Answer 41

Store and concentrate bile

Question 42

How does the wall of the gallbladder differ from the general layout of the gut tube?

Answer 42

Only 3 layers, missing submucosa

Question 43

What are the layers of the gallbladder wall?

Answer 43

Mucosa Muscularis Serosa

Question 44

What is the serosa of the gallbladder formed from?

Answer 44

Connective tissue

Question 45

What is the purpose of the muscularis layer of the gallbladder?

Answer 45

Smooth muscle for contraction

Question 46

What is the structure of the mucosa of the gallbladder?

Answer 46

Foled (rugae) for expansion

Question 47

What is the pathway from the gallbladder to the common bile duct?

Answer 47

Gallbladder -\> cystic duct -\> common bile duct

Question 48

What controls the release of bile and pancreatic juice into the duodenum?

Answer 48

Sphincter of Oddi

Question 49

What happens to bile when the sphincter of Oddi contracts?

Answer 49

Sphincter closes which forces bile back into the gallbladder

Question 50

To what extent does the gallbladder concentrate bile?

Answer 50

5-20x

Question 51

Why does the gallbladder absorb Na?

Answer 51

Due to chemical gradient created by Na/K ATPase

Question 52

Explain the mechanism for the release of bile in relation to fat being present in the duodenum?

Answer 52

1) CCK is released 2) CCK acts on sphincter of Oddi causing it to relax 3) CCK acts on gallbladder causing it to contract 4) Bile is discharged into duodenum causing fat solubilisation 5) CCK acts on pancreatic enzymes increasing bile secretion

Question 53

Why is it important that CCK controls both bile and pancreatic enzyme secretion at the same time?

Answer 53

Need both bile and lipase to digest fat

Question 54

Considering the difference in secretin and CCK, what is the function of each?

Answer 54

Secretin is used for neutralisation CCK is used for digestion

Question 55

What causes the secretion of secretin?

Answer 55

Acid in the duodenum

Question 56

What effects does secretin have?

Answer 56

Decreases acid secretion Decreases acid emptying Increases HCO₃ duodenal secretion Increases HCO₃ pancreatic secretion Increases HCO₃ bile duct secretion

Question 57

What inhibits the secretion of secretin?

Answer 57

Neutralisation (negative feedback loop)

Question 58

What causes the secretion of CCK?

Answer 58

Fat/amino acid in the duodenum

Question 59

What effects does CCK have?

Answer 59

Decreases gastric emptying Increases pancreatic enzyme secretion Gallbladder contraction Relaxation of sphincter of Oddi

Question 60

Does anything inhibit the secretion of CCK, creating a negative feedback loop?

Answer 60

No

Question 61

What does CCK stand for?

Answer 61

Cholecystokinin