Liver Structure and Function Flashcards

1
Q

What is the largest organ in the body?

A

The liver which weights about 1.4kg

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2
Q

Where is the liver located within the abdomen?

A

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

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3
Q

How many lobes does the liver contain?

A

4

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4
Q

What are the 4 lobes of the liver?

A

Left lobe

Right lobe

Caudate lobe

Quadrate lobe

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5
Q

On what surface is the portal of the liver?

A

Posterior

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6
Q

Whats enters and exits the liver through the porta?

A

Blood vessels (hepatic portal vein, hepatic artery)

Lymphatic vessels

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

Nerves (hepatic nerve plexus)

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7
Q

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

A

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

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

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8
Q

What does the coronary ligament attach the liver to?

A

Inferior surface of diaphragm

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9
Q

What is the liver covered by?

A

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

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10
Q

Where is the bare area of the liver?

A

Diaphragmatic surface surrounded by coronary ligament

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11
Q

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

A

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

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12
Q

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

A

Septa

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13
Q

What does the septa divide the liver into?

A

Hexagonal lobules

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14
Q

What forms the portal triad?

A

Hepatic portal vein, hepatic artery and hepatic duct

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15
Q

Where are portal triads found?

A

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

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16
Q

What is at the centre of each lobule?

A

Central veins

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17
Q

What do central veins of lobules go onto become?

A

Hepatic veins then inferior vena cava

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18
Q

Explain the surroundings of central veins of lobules?

A

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

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19
Q

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

A

Hepatocytes

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20
Q

What are spaces between hepatic cords called?

A

Hepatic sinusoids

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21
Q

What are hepatic sinusoids?

A

Blood channels

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22
Q

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

A

Blood travels towards the central vein

Bile travels away from the central vein

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23
Q

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

A

Blood high with oxygen and nutrient content

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24
Q

Why is glucose stored in the liver as glycogen?

A

Glucose would be a problem osmotically

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25
Q

What is the alimentary role of the liver?

A

Produce and secrete bile

26
Q

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

A

Hepatic portal vein

27
Q

What would we not be able to do without bile?

A

Digest fats

28
Q

What are the 6 components of bile?

A

Bile acids

Lecithin

Cholesterol

Bile pigments

Toxic metals

Bicarbonate

29
Q

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

A

Toxic metals

Bicarbonate

30
Q

What are bile pigments broken down from?

A

Haemoglobin from old/damaged erythrocytes

31
Q

What are the different kinds of bile pigments?

A

Bilirubin extracted from blood by hepatocytes (yellow)

Bilirubin modified by bacterial enzymes (brown)

Bilirubin reabsorbed from excreted urine (yellow)

32
Q

What are bile salts synthesised in the liver from?

A

Cholesterol

33
Q

How much bile salt is produced per day?

A

0.5g

34
Q

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

A

10g

35
Q

Why is 0.5g of bile salt synthesised everyday?

A

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

36
Q

What happens to bile acids before secretion?

A

Conjugate with glycine or taurine to form bile salts

37
Q

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

A

Increases solubility

38
Q

How are excreted bile salts recycled?

A

Via enterohepatic circulation:

liver -> bile duct -> gallbladder -> bileduct (returns) -> duodenum -> ileum -> hepatic portal vein -> liver etc

39
Q

What is the size of the gallbladder?

A

8cm wide x 4cm long

40
Q

Where is the gallbladder found?

A

Inferior surface of liver

41
Q

What is the function of the gallbladder?

A

Store and concentrate bile

42
Q

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

A

Only 3 layers, missing submucosa

43
Q

What are the layers of the gallbladder wall?

A

Mucosa

Muscularis

Serosa

44
Q

What is the serosa of the gallbladder formed from?

A

Connective tissue

45
Q

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

A

Smooth muscle for contraction

46
Q

What is the structure of the mucosa of the gallbladder?

A

Foled (rugae) for expansion

47
Q

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

A

Gallbladder -> cystic duct -> common bile duct

48
Q

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

A

Sphincter of Oddi

49
Q

What happens to bile when the sphincter of Oddi contracts?

A

Sphincter closes which forces bile back into the gallbladder

50
Q

To what extent does the gallbladder concentrate bile?

A

5-20x

51
Q

Why does the gallbladder absorb Na?

A

Due to chemical gradient created by Na/K ATPase

52
Q

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

A

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

53
Q

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

A

Need both bile and lipase to digest fat

54
Q

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

A

Secretin is used for neutralisation

CCK is used for digestion

55
Q

What causes the secretion of secretin?

A

Acid in the duodenum

56
Q

What effects does secretin have?

A

Decreases acid secretion

Decreases acid emptying

Increases HCO3 duodenal secretion

Increases HCO3 pancreatic secretion

Increases HCO3 bile duct secretion

57
Q

What inhibits the secretion of secretin?

A

Neutralisation (negative feedback loop)

58
Q

What causes the secretion of CCK?

A

Fat/amino acid in the duodenum

59
Q

What effects does CCK have?

A

Decreases gastric emptying

Increases pancreatic enzyme secretion

Gallbladder contraction

Relaxation of sphincter of Oddi

60
Q

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

A

No

61
Q

What does CCK stand for?

A

Cholecystokinin