liver metabolism

Question 1

what circulation drains the gut?

Answer 1

portal circulation

Question 2

what is a hepatic lobule?

Answer 2

structural unit of the liver

Question 3

how does blood enter a hepatic lobule?

Answer 3

enters via portal venule and the hepatic arteriole

Question 4

how does all dietary carbohydrate reach the liver?

Answer 4

as glucose

Question 5

what is sucrose broken down into?

Answer 5

fructose and glucose

Question 6

what is lactose broken down into?

Answer 6

galactose and glucose

Question 7

what is starch broken down into?

Answer 7

maltose and glucose

Question 8

what is glycogenesis?

Answer 8

glucose –> glycogen

Question 9

what is glycogenolysis?

Answer 9

breaking down of glycogen

Question 10

in the presence of oxygen, what process does glucose feed into?

Answer 10

Krebs cycle

Question 11

how can hepatocytes generate glucose?

Answer 11

gluconeogenesis from materials such as lactate, pyruvate, amino acids and glycerol

Question 12

what are the functions of insulin?

Answer 12

Counteracted by glucagon.
Promotes glycogen synthesis
Suppresses gluconeogenesis
Accelerates glycolysis

Question 13

what are essential amino acids?

Answer 13

need to be taken up through diet

Question 14

what is transamination?

Answer 14

transfer of amino group to keto-acid catalysed by transaminase

Question 15

what are alanine and aspirate aminotransferases indicators of?

Answer 15

hepatic injury

when hepatocytes die they release this enzyme

Question 16

what is deamination?

Answer 16

removing an amino group

Question 17

what does deamination form?

Answer 17

often forms a keto acid and an ammonium ion

Question 18

why is excess ammonia dangerous?

Answer 18

depletes ketoglutarate which is used in Krebs cycle
increases level of glutamate
increases osmotic pressure
astrocytes swell
increases cranial pressure

Question 19

how is ammonia produced?

Answer 19

deamination and gut bacteria

Question 20

how is ammonia removed from the body?

Answer 20

NH3 reduced to NH4

NH4 –> urea through urea cycle

Question 21

what is raised serum urea an indicator of?

Answer 21

renal failure bc urea is secreted into the kidneys

also could show there’s too much ammonia

Question 22

what is plasma?

Answer 22

liquid component of blood- cell free

Question 23

what does plasma contain?

Answer 23

albumin, globulins, clotting factors, water, glucose and electrolytes

Question 24

where are most plasma proteins made?

Answer 24

in the liver

Question 25

what is blood serum?

Answer 25

blood without the clotting factors

Question 26

how are lipids transported?

Answer 26

lipoproteins

Question 27

what are lipoproteins?

Answer 27

arrangement of phospholipid layer with non-soluble material on the inside

Question 28

what can triglycerides be broken down into?

Answer 28

fatty acids and glycerol

Question 29

how can fatty acids be used?

Answer 29

to make acetyl coA --> respiration, cholesterol synthesis

Question 30

how can glycerol be used?

Answer 30

can be converted to glucose in gluconeogenesis

Question 31

what does the liver do with excess glucose?

Answer 31

excess glucose to fatty acids, synthesizes phospholipids and ketone bodies

Question 32

when does ketogenesis occur?

Answer 32

in the absence of glucose - switched off by insulin

Question 33

what does ketogenesis do?

Answer 33

breaks down lipids and proteins | fatty acids can then be converted to acetyl coA to produce ketone bodies

Question 34

what is bile?

Answer 34

emulsifier that dissolves fat

Question 35

what organ makes bile?

Answer 35

the liver

Question 36

where is bile stored?

Answer 36

the gall bladder

Question 37

which cells secrete bile?

Answer 37

hepatocytes in canaliculi

Question 38

what is bile made of?

Answer 38

water (>90%), bile salts, bilirubin, cholesterol, fatty acids, lecithin, Na+/K+/Ca2+/Cl-

Question 39

what are cholangiocytes and what are their function?

Answer 39

epithelial cells of the bile ducts, can modify bile (production) by the addition of HCO3-

Question 40

what does CCK stimulate?

Answer 40

gall bladder contraction and sphincter of Oddi relaxation

Question 41

what stimulates the secretion of CCK?

Answer 41

in response to fatty acids being in the lumen of the duodenum

Question 42

what stimulates the secretion of secretin?

Answer 42

presence of acidic chime in duodenum

Question 43

what is formed when cholesterol is oxidised?

Answer 43

cholic acid and chenodeoxylic acid

Question 44

where are bile salts absorbed?

Answer 44

in the ileum

Question 45

if bile salts are not reabsorbed, where do they move?

Answer 45

to the colon

Question 46

what can bile salts in the colon cause?

Answer 46

diarrhea due to the increased oncotic pressure of bile salts in the lumen

Question 47

what is exogenous cholesterol?

Answer 47

cholesterol from the diet

Question 48

what is endogenous cholesterol?

Answer 48

cholesterol synthesised in the liver

Question 49

what effect do statins have on the endogenous products of cholesterol?

Answer 49

inhibit

Question 50

where are red blood cells broken down?

Answer 50

in the spleen

Question 51

what is haemoglobin broken down into?

Answer 51

heme and globin

Question 52

what does the non-heme part of haemoglobin turn into?

Answer 52

bilirubin

Question 53

what protein does bilirubin bind to?

Answer 53

albumin

Question 54

what is the cause of jaundice?

Answer 54

build up of bilirubin