L24 - Liver Anatomy And Function

Question 1

What are the four lobes in the liver?

Answer 1

• left
• right
• caudate
• quadrate

Question 2

What is the superios upper face of the liver called?

Answer 2

Diahphragmatic surface

Question 3

Where is the gallbladder located?

Answer 3

Visceral surface
- faces adj abdominal organs (downwards)

Question 4

What is the liver made up of? What does it contain?

Answer 4

Lobules
- hepatocytes, blood vessels, bile canliculi

Question 5

What is the portal triad?

Answer 5

• bile duct
• portal vein
• hepatic artery

Question 6

Where does liver receive blood from? (2)

Answer 6

• heart
• GI tract

Question 7

What does the hepatic portal vein deliver?

Answer 7

Poorly oxygenatwd blood from the GI tract

Question 8

What does the hepatic artery deliver?

Answer 8

Oxygenated blood from the heart

Question 9

Why does the hepatic portal vein and the hepatic artery divide into two?

Answer 9

To supply left and right side of the liver

Question 10

Where does blood flow? And where does bile flow?

Answer 10

Blood - hepatic portal vein and hepatic artery to central vein
Bile - opposite direction

Question 11

What are the hepatic functions of the liver? (6)

Answer 11

• exocrine (digestive, bile salts and HCO3-)
• cholesterol metabolism
• organic and drug metabolism
• endocrine (peptides and hormones)
• clotting (plasma cf)
• secretes plasma proteins

Question 12

What is bile synthesised by? Where is it stored?

Answer 12

• liver
• in the gallbladder

Question 13

What are the components produced by? (2)

Answer 13

• hepatocytes
• epithelial cells

Question 14

What do hepatocytes produce in the exocrine function? (4)

Answer 14

• bile salts (solubilise fats)
• cholesterol
• phospholipids
• bile pigments

Question 15

What do epithelial cells produce in the exocrine function?

Answer 15

• HCO3- (neutralises stomach acid
  = secretion triggered by secretin from SI in response to FA in diet

Question 16

During a meal, what does the gall bladder do? What is it stimulated by?

Answer 16

• contracts and releases bile into duodenum via sphincter of oddi
• stimulated by cholecystokinin from SI (triggered by FA)

Question 17

What is the enterohepatic circulation?

Answer 17

Flow and release of bile/bile salts

Question 18

What happens to bile salts during a fatty meal?

Answer 18

Absorbed into SI by Na+ coupled transporters

Question 19

What do hepatocytes absorb?

Answer 19

Bile salts from the blood
- secrete back into bile

Question 20

What are new bile salts synthesised from?

Answer 20

cholesterol

Question 21

Where does the liver extract salts cholesterol from? What does it secrete it into?

Answer 21

• from the blood
• into bile/faeces

Question 22

What is cholesterol like?

Answer 22

Insoluble but forms micelles

Question 23

What does the sequestering of bile in SI by dietary fibres prevent?

Answer 23

Enterohepatic recirculation

Question 24

What is cholesterol required for? Where is it synthesised in the body?

Answer 24

• membrane, bile synthesis, precursoe to steroid hormones
• liver by HMG-CoA

Question 25

How are cholesterol level maintained in normal range?

Answer 25

Increased dietary cholesterol supressing HMG-CoA

Question 26

Where are saturated fatty acids found in? What does it do to plasma cholesterol?

Answer 26

- red meat/cheese/whole milk - increases plasma cholesterol

Question 27

Where are polyunsaturated/monounsaturated fatty acids found in? What does it do to plasma cholesterol?

Answer 27

- olive/peanut oil - decrease plasma cholesterol

Question 28

How does cholesterol circulate?

Answer 28

Lipoprotein complexes (chylomicrons, etc.)

Question 29

What do low density lipoprotein cholesterol carriers do?

Answer 29

Deliver cholesterol to cells

Question 30

What do high density lipoproteins do?

Answer 30

Remove cholesterol from plasma and deliver to liver

Question 31

What is atherosclerotic disease?

Answer 31

Deposition of cholesterol in arter walls = increased risk of heart attack

Question 32

What are important factors for atherosclerotic disease?

Answer 32

Ratio of LDL to HDL - smoking dec HDL, wl inc it - oestrogen lowers LDL, raises HDL

Question 33

What is familial hypercholesterolaemia?

Answer 33

decreased LDL receptors - inc circulating cholesterols

Question 34

What are gallstones?

Answer 34

Crystallisation of cholesterol in gallbladder

Question 35

What do gallstones lead to? (4)

Answer 35

- blocked gallbladder/bile duct = prevents fat digestion/absorption) - dec in absorption of fat soluble vitamins (ADE), clotting problems - bacteria acting on unabsorbed fat = diarrhoea, fluid loss - blocked pancreatic secretions = build up of bilirubin

Question 36

What is jaundice?

Answer 36

Excess bilirubin (Can occur in liver disease and haemolytic anaemia)

Question 37

What are the plasma proteins? (3)

Answer 37

- albumin - globulins (immunoglobuling/abods) - fibrinogen (blood clotting cascade)

Question 38

Where is albumin synthesised, circulate and its function? (3)

Answer 38

- liver - plasma - osmolarity of plasma, carrier molecule for substances/drugs

Question 39

What is the bile in the liver essential in the absorption of?

Answer 39

Lipid soluble vitamin K in SI

Question 40

What is vitamin K essential for?

Answer 40

Production of prothrombin (cf)

Question 41

What does the liver secrete in response to inc levels of GH?

Answer 41

Insuling-like growth factor -1 (IGF-1)

Question 42

What does IGF-1 do?

Answer 42

Act in synergy with GH = bone choncdrocytes to undergo cell div

Question 43

What does liver hydroxylase enzymes metabolise?

Answer 43

Dietary (D2), sunlight-derived (D3) vit D to 1,25-(OH)2D-calcitriol (actiive form)

Question 44

What does calcitrol stimulate?

Answer 44

SI absorption of calcium required for bones

Question 45

What does the liver do in the homeostatic function? (3)

Answer 45

- produce angiotensinogen (cleaved = angiotensin I by the action of renin) - renin secreted by kidneys (drop in BP) - activation og AngI to AngII = vasoconstriction and Na+/H2O retention

Question 46

What is does the liver do in the immune function? (3)

Answer 46

- key detector of pathogens through GI tract - filets blood from hepatic portal vein - pathogens detected by macrophage-like (kupffer) cells

Question 47

What are liver diseases and what are they caused by? (6)

Answer 47

- alcoholic liver disease (exc alc) - non-alcoholic liver disease (obesity) - hepatitis (viral infection, exc alc) - haemochromatosis (gen disease, build of Fe) - cirrhosis (liver scarring, failure//viral, alc,drugs, metabolic factors) - hepatotoxic medications (drug induced)