Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

GI > Liver > Flashcards

Liver Flashcards

(104 cards)

Start Studying
1
Q

How much of the blood supply to the liver is from the hepatic portal vein?

A

75%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Why can the liver be described as a factory?

A

metabolism: CHO, proteins, lipids
synthesis: bile, proteins, nucleotides, cholesterol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what waste management does the liver carry out?

A

internal waste products e.g. bilirubin, ammonia, hormones (insulin, growth hormones, oestogen)
treats hazardous material e.g. food toxins, drugs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what 2 components are found in the space of disse?

A

collagen, stellate cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is the function of stellate cells

A

contractile

control connective tissue turnover and collagen synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what percentage of liver cells do hepatocytes contribute to and what is their function?

A

60%

most metabolic functions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

where are kupffer cells found and what do they do?

A

in sinusoidal lining

remove antigens, produce cytokines, immune ‘sieving’ system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what are pit cells?

A

liver associated lymphocytes

NKCs –> protect from viruses/ tumours

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is the immunological function of the liver?

A

degrades bacteria and antigens

kupffer cells –> immunoglobulins, TNF, collagenase, lysosomal hydrolases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what are the 3 internal waste products that the liver disposes of?

A

bilirubin, ammonia –> urea, hormones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are xenobiotics?

A

potentially toxic compounds such as food toxins, drugs, food addictives

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

how many phases are involved in the metabolism of xenobiotics?

A

2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what occurs in the 1st stage of xenobiotic metabolism?

A

Cytochrome P450 enzyme
oxidation (oxygen donor), reduction (required NADH), hydrolysis, hydroxylation
–> MORE REACTIVE COMPOUND
in ER

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what happens during the 2nd phase of xenobiotic metabolism?

A

conjugation - glucuronyl, acetyl, sulphate, glycyl, methyl groups added
occurs in liver, lungs, kidney
INACTIVE PRODUCTS MORE WATER SOLUBLE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

how are xenobiotics eventually excreted from the body?

A

in urine or bile

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

how does the alcohol metabolism pathway change with chronic alcohol consumption?

A

induced CP450 production so more metabolised by this pathway

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

which enzyme is involved in the 1st stage of alcohol metabolism and where does this occur?

A

alcohol dehydrogenase in the cytosol of hepatocytes –> acetaldehyde

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What happens to NAD during alcohol metabolism?

A

reduced to NADH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What happens during the 2nd stage of alcohol metabolism and where does this take place?

A

acetaldehyde dehydrogenase:

acetaldehyde –> acetate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what is the product of alcohol metabolism and what happens to it?

A

acetate –> acetyl coA –> krebs cycle –> ATP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Which cofactor is required for phase 1 xenobiotic metabolism?

A

NADPH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

where do phase 2 xenobiotic metabolism reactions occur?

A

liver, kidney, lungs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Why is xenobiotic metabolism a problem with pharmacology?

A

ist pass metabolism –> inactives srug if taken orally –> poor bioavailability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

where are RBCs disposed of?

A

spleen, liver, bone marrow by kupffer cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
where is haem degraded to bilirubin?
kupffer cells
26
how is haem degraded to bilirubin?
haem --> biliverdin --> bilirubin | NADPH required at each step
27
what colour is biliverdin?
green
28
what colour is bilirubin?
yellow
29
how is bilirubin transported to the liver hepatocytes?
attached to albumin
30
what happens to bilirubin in the liver hepatocytes?
conjugated mainly with glucuronic acid
31
is conjugated bilirubin secretion active or passive?
active
32
where is conjugated bilirubin secreted into?
bile canaliculi --> bile --> intestines
33
how is urobilinogen formed?
bacteria in the gut convert bilirubin to urobilinogen
34
why is urine yellow?
contains urobilin = derivative of bilirubin
35
why is faeces brown?
contains stercobilin | bilirubin --> stercobilinogen --> oxidised to stercobilin
36
why does jaundice occur?
problem with haem degredation
37
why might pre-hepatic jaundice occur?
overload of haem | haemolytic anaemia breaking down RBCs
38
why might intra-hepatic jaundice occur?
liver damage | Gilbert's syndrome
39
which forms of jaundice result in raised unconjugated bilirubin levels?
pre-hepatic and intra-hepatic
40
why might extra-hepatic jaundice occur?
obstruction to bile duct e.g. blockage from gallstones, pancreatic carcinoma
41
what is globin degraded to?
amino acids
42
What are the 2 things that dietary amino acids can be use for?
synthesis of new compounds | breakdown for energy
43
Name 6 types of N containing metabolites
haem, NTs (dopamine, noradrenaline, adrenaline) | serotonin, histamine, creatinine, purine bases
44
which amino acid forms histamine?
histidine
45
which 3 AAs form purine bases?
glycine, aspartate, glutamine
46
why must the amino group be removed from AAs before they are used for energy?
ammonia is very toxic so blood levels must be kept very low
47
what are the symptoms of hyperammonia?
tremor vomiting cerebral oedema death
48
why might hyperammonia arise?
genetic defect - urea cycle enzyme deficiencies | liver disease
49
what is kwashiorkor?
protein deficiency disease
50
what are the symptoms of kwashiorkor?
abdominal bloating, lower leg oedema, poor nutrient absorption, poor skin condition, hair/skin colour changes, susceptible to infection
51
why does kwashiorkor result in hair and skin colour changes?
melanin = nitrogen containing (from amino acids)
52
which 3 ways can the carbon skeleton of AAs be used?
ketogenic pathways --> fatty acids and ketone bodies glucogenic pathways --> glucose precursors, gluconeogenesis --> glucose krebs cycle --> ATP (All AAs)
53
which 2 amino acids cannot be used in gluconeogenesis and why?
leucine, lycine because they only form acteyl coA --> carbon atoms released as CO2
54
when are AAs used for fatty acid synthesis?
storage
55
when are ketone bodies formed from AAs?
fasting
56
When are AAs used for gluconeogenesis?
fasting, exercise
57
where does gluconeogenesis occur?
liver and kidney mainly in cytosol
58
what 3 compounds can be used in gluconeogenesis to produce glucose?
anaerobic respiration --> lactate AAs --> keto acids triacylglycerol --> glycerol
59
which AA in particular can be used in gluconeogenesis?
alanine
60
what is the Cori cycle?
helps to maintain muscle metabolism by removing lactate from anaerobic respiration --> used in liver to produce glucose
61
what are the 3 stages of amino group removal?
transamination, deamination, urea cycle
62
where does transamination occur and what happens?
peripheral tissues amino group from AAs attached to a-ketoglutarate to form glutamate extra amino group --> glutamine
63
which enzyme is involved in transamination?
transaminase
64
which cofactor is required for transamination?
Pyroxidal phosphate (active form of vit. B6)
65
what symptoms arise from a lack of B6 (pyroxidal phosphate)
poor growth, skin lesions, poor immune response (synthesis of AAs) neurological symptoms (required for energy metabolism and NT synthesis) anaemia (required for haem synthesis)
66
where does deammination occur?
liver hepatocytes
67
which enzyme is required for deamination?
glutamate dehydrogenase
68
why must transamination occur?
to transport toxic ammonia in the blood to the liver
69
where does the urea cycle occur?
in mitochondria and cytosol of liver hepatocytes
70
which 2 compounds enter the urea cycle?
CO2 and NH3
71
what is the control step of the urea cycle?
formation of carbamoyl phosphate
72
which enzyme is responsible for carbamoyl phosphate synthesis?
carbamoyl phosphate synthetase 1
73
what role does N-acetyl glutamate play in the control step of the urea cycle?
N-actyl glutamate allosterically activates carbamoyl phosphate synthetase 1, which is required for the synthesis of carbamoyl phosphate high levels of glutamate forms N-acetyl glutamate high levels of AAs activate the urea cycle
74
what is uric acid?
formed from purine nucleotides
75
what are the symptoms of hyperuricaemia?
``` kidney stones (sodium urate crystals in kidneys) gout (sodium urate crystals in joints) ```
76
why might hyperuricaemia occur?
too much high purine foods (red meat seafood) poor excretion from kidneys over-production of urate
77
which protein is not synthesised in the liver?
gamma globulins
78
what are the 3 control steps in glycolysis?
glucose --> glucose -6-phosphate fructose-6-phosphate --> fructose 1,6-bisphosphate phosphoenolpyruvate --> pyruvate
79
which enzyme converts glucose to glucose-6-phosphate?
hexokinase/ glucokinase
80
which enzyme converts fructose 6 phosphate to fructose 1,6 bisphosphate?
phosphofructokinase
81
which enzyme converts phosphoenolpyruvate to pyruvate?
pyruvate kinase
82
which enzyme is the main control point for glycolysis?
phosphofructokinase
83
where does glycolysis take place?
in the cytoplasm
84
what are the 3 main factors that activate phospho-fructokinase?
high AMP (allosteric activation), insulin (alters transcription to increase gene expression), F2,6-bisP
85
what effect does glucagon have on glycolysis and where does it affect the pathway?
inhibits production of F2,6-bisP therefore inhibits phosphofructokinase glucagon dephosphorylates an enzyme which inhibits F2,6 bisP
86
what are high levels of AMP indicative of and why?
low energy levels because 2 ADP join together to form ATP and AMP (enzyme = adenylate kinase) AMP-activated protein kinases activate key enzymes
87
how many pyruvate molecules are formed from one molecule of glucose?
2
88
how many NAD coenzymes are required in glycolysis?
2 (to produce 2 pyruvate)
89
how many ATP are directly made from glycolysis?
2
90
overall including oxidative phosphorylation how many ATP can be make from aerobic glycolysis?
5-7 (2 directly and a further 3-5 from oxidative phosphorylation of 2 NADH)
91
how does glucagon inhibit glycolysis?
phosphorylates an enzyme that inactivate F2,6BisP
92
what inhibits hexokinase/glucokinase and what is this an example of?
product inhibition from glucose 6 phosphate
93
which 2 enzymes are key to guconeogenesis?`
fructose 1,6 bisphophatase | glucose 6 phosphatase
94
where do alanine and lactate enter gluconeogenesis?
converted into pyruvate
95
does ATP inhibit gluconeogenesis or glycolysis?
glycolysis (because signals high energy state) | inhibits phosphofructokinase and pyruvate kinase
96
what 4 factors regulate the activity of fructose1,6 bisphosphatase in gluconeogenesis?
AMP, insulin --> inhibit | citrate, glucagon --> activate
97
which enzyme is involved in breaking down glucagon into glucose 1 phosphate?
glycogen phosphorylase
98
in which organs can glycolysis produce glucose?
liver and kidneys
99
why can't glucose be released from muscle tissue?
glucose 1 phosphate can't be broken down into glucose as lacking the enzyme for conversion (glucose 6 phosphatase)
100
how many ATP/ GTP are required for gluconeogenesis to take place?
6
101
why does alcohol inhibit gluconeogenesis and make you feel hungry?
alcohol metabolism produces NADH which favours the conversion of alanine to pyruvate then to lactate not lactate to pyruvate. glyceraldehyde is also converted back to glycerol. Gluconeogenesis is therefore inhibited
102
what are the 2 phases of glycolysis?
preparative phase | generating phase
103
what is produced in the preparative phase?
fructose 1,6-bisphosphate
104
why is ATP needed for the first step of glycolysis?
to activate glucose by phosphorylating it

GI (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions