Block 4 week 10

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103 Terms

1
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how many functional segments of the liver are there?
9
2
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why is it said that the liver has dual blood supply
receives:
- oxygenated blood from heart via hepatic artery
- nutrient rich slightly deoxygenated blood from from gut via hepatic portal vein
3
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liver is composed of smaller structures called lobules. what are lobules surrounded by?
branches of hepatic artery and portal vein
4
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what are sinusoids?
specialized capillaries with large pores
5
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sinusoids have increased permeability compared to capillaries what does this mean about the type of molecules which can cross
it allows larger molecules such as proteins to cross
6
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how is increased permeability of sinusoids achieved
- incomplete surrounding basement membrane.
- endothelial layer contains large intercellular gaps
7
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What are kuffer cells?
macrophages in the liver
8
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what are sinusoidal endothelial cells?
line the sinusoidal blood vessels
9
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what are stellate cells?
found in peri-sinusoidal space, activated in response to damage
10
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What are hepatocytes?
liver cells - which are extremely metabolically active
11
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What are cholangiocytes?
epithelial cells lining the bile ducts
12
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what is released in amino acid break down which is potentially toxic
amine group
13
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how does the liver remove the amine group from amino acids which is potentially toxic?
deamination
converts it to urea which is a harmless product which can then be excreted by kidneys
14
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what if excess glucose stored as
glycogen
15
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what does the liver convert excess carbohydrates and proteins to?
fats
16
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what are the different type of lipoproteins export cholesterol to cells
HDL and LDL
17
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what is a surplus of cholesterol converted to?
bile salts by the liver
18
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Retinol is carried in the bloodstream bound in a complex with TTR.
what is TTR?
a protein made in the liver
19
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what is vitamin a important for?
eye health
20
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in some immune cells retinol is converted to retinoic acid why?
retinoic acid is very metabolically active and can be delivered to cell which need it
21
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how are toxic compounds made easier to excrete
often toxic compounds are fat soluble so by converting them into water soluble compounds they are easier to excrete
22
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what are the two steps of detoxification?
phase 1: fat soluble toxins are processed by oxidation, reduction and hydrolysis reactions
phase 2: toxin or metabolites from phase 1 is conjugated to another compound which is less harmful and makes it more water soluble so can be excreted easily
23
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phase 1 detoxification produces free radicals. what neutralises them?
antioxidants
24
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which plasma proteins are produced in the liver
albumins
globulins
fibrinogens
25
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What is the role of albumin?
regulates osmotic pressure
26
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what is the role of globulins?
transport and antibodies
27
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What is the role of fibrinogen?
part of the clotting cascade, forms a fibrin clot
28
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where is bile produced?
liver
29
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bile is secreted into the small intestine by \----------
hepatocytes
30
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cholangiocytes modify bile \______________ and composition
volume
31
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what is the purpose of bile
To emulsify lipids increasing the surface area for lipases to act
32
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how is bile recycled?
bile salts which enter the small intestine can be reabsorbed into the hepatic portal vein
33
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what is a colloid?
a homogenous non-crystalline substance consisting of large molecules of one substance dispersed in another
34
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what are the two categories of colloids?
lyophilic and lyophobic
35
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what are the characteristics of lyophilic colloids?
- affinity for medium is high (like solvent dispersed into)
- spontaneous formation of colloidal dispersion
36
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what are the characteristics of lyophobic colloids?
- do not like solvent dissolved in
- needs energy to be provided
- preparation requires breaking large particles into particles of colloidal dimensions
37
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what are the different preparation methods for colloidal dispersions?
dispersion method:
- colloidal mill
- ultrasonic treatment
condensation methods:
- supersaturated solutions
38
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colloids are polydisperse. what does this mean?
multiple different size and shape particles
39
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colloids can form many shapes. give some examples of the different polymers which could form these shapes
- Lipophilic polymers when in water tend to form long chains which are coils
- Proteins such as albumin are spherical
- Peptides and short fragments of DNA can be seen as rods
40
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what is viscosity
the resistance to flow
41
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what can light diffraction be used to determine?
size and molecular weight
42
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ionic substances will be charged by an (equal/unequal) dissolution of the opposite charged ions? is the correct word for this sentence equal or unequal
unequal
43
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what is the charge of the colloid controlled by?
the ionisable surface grouping
44
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what is ion adsorption in relation to colloids?
the net surface charge acquired by unequal adsorption of the oppositely charged ions
45
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what do frequent encounters between colloids lead to?
coagulation
aggregation
flocculated particles
dispersed particles
46
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what factors effect the stability of lyophobic colloidal systems
electrical forces of repulsion
forces of attraction
47
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what factors effect the stability of lyophilic systems
solvation
48
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in a lyophilic colloid:
if the primary maximum is greater than the thermal energy then the system is stable and if the primary maximum is less than the thermal energy then the system is unstable. what does an unstable system lead to?
formation of aggregates
49
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what happens to lyophobic colloidal systems when electrolytes are added
No electrolytes there is maximum repulsion
Adding electrolytes will lead to weakening of repulsive forces and a generation of primary maximum and a secondary minimum
Adding too many electrolytes will lead to system being destabilised as collides are able to get into contact
50
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lyophilic colloid systems use a combination of electric double layer interactions and solvation, how is this destabilised
adding high amount of electrolytes, water of solvation is lost leading to salting out effects
51
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polymer materials can adsorb on surface and stabilise lyophobic colloidal systems how?
by steric interaction between particles leading to repulsion - entropic stabilisation
52
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what are dispered systems
a dispersed system consists of particles in one phase dispersed in another
53
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why is a large surface area to volume ratio needed in a dispersed system
as the dispersed phase is never solubilised on the continuous phase leading to surface tension which needs to be reduced
54
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how can surface tension of dispersed phase be reduced?
particles associating and aggregating
55
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what are polymers?
macromolecules made of monomers
56
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what is a monomer which carries a charge called?
an electrolyte
57
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what does mean when it says polymers are poly dispersed?
some chains will be longer than others
58
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what is a homopolymer?
a polymer made of a single monomer
59
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What is a copolymer?
a polymer made up of different monomers
60
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what happens to the viscosity of the solution if a hydrophilic polymer was placed in water?
the viscosity will increase as the polymer will attract water molecules
61
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what happens if a hydrophilic polymer was placed in an organic substance?
will minimise the surface area to reduced the surface tension
62
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why can very large polymers show crystalline region at high concentrations?
as the order between monomers can mimic the organisation of crystals
63
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give some examples of the uses of polymers
- excipients in tablets
- coating
- controlled drug release
- excipients in semi- solid preparations
- adhesive polymers for skin delivery
64
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how are gels formed?
aggregation of colloid solid particles.
- particles are often polymers which form an interface network
65
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how is gelation obtained
having a continuous floccule. Floccules are loose aggregates of sols obtained at specific experimental conditions in which attractive and repulsive forces allows for solids to come in close contact, move together but then dissociate after a while
66
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what are the two types of lyophilic gels
type 1 ( chemical)
type 2 (physical)
67
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how do surfactants work?
Reduce the surface tension by placing themselves at the interface of interest as surfaces have two distinct regions: hydrophobic and hydrophilic (said to be amphipathic)
68
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what are the different types of pharmaceutical uses of surfactant
stabilise emulsions, formation of suspensions, improve wetting of solids, used in drug delivery systems, stabilise monoclonal therapeutic antibodies
69
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name the 4 types of surfactant
anionic
non-ionic
cationic
zwitterionic
70
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what is the difference between a regular micelle and an inverted micelles
with a regular micelle the hydrophobic tail is on the inside and the hydrophilic head is on the outside whereas with inverted micelles the hydrophobic tails is on the outside and the hydrophilic head is on the inside
71
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explain how micelles form
- Adding surfactant in aqueous solution move to the interface and start to decrease the surface tension
- The more surfactant added the more the surface tension is decreased. This is true until interface is covered.
- When interface is covered additional surfactant added cannot move to the interface so start to form micelles
72
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what are the three main course of liver disease?
alcohol
non-alcoholic fatty liver disease
viral hepatitis
73
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what is the advice for drinking alcohol
it is recommended to not drink more than 14 units of alcohol a week and it should be spread across three or more days
74
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fats are metabolised in the liver to form \_____________ which are released into the circulation
lipoproteins
75
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what happens when there is an excess of triglycerides or blockage of the release of lipoproteins?
there is a build up of fat in liver cells
76
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what are some risk factors of non-alcoholic fatty liver disease (NAFLD)
- obesity
- increased visceral fat
- insulin resistance
- lack of exercise
77
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what are the four stages of NAFLD?
1.accumualtion of fat in cells
2. inflammation due to accumulation of fats
3. inflammation has led to scarring in the liver
4. irreversible liver damage
78
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can hepatitis A progress to chronic liver disease
No
79
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hepatitis D can only replicate in presence of hepatitis B what does this combination lead to?
increased risk of progression of liver disease
80
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why is hepatitis C known as the silent killer
the majority of those who are diagnosed are asymptomatic, and it leads to slow progressive liver disease
81
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do patients with pre-existing liver disease have increased susceptibility to develop hepatotoxicity
no they do not have increased susceptibility they may be more severe due to reduced hepatic reserve
82
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what is a intrinsic reaction (drug induced liver disease)
- predictable
- dose dependent
- occur very rapidly
- tend to cause acute liver failure
83
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What is an idiosyncratic reaction? (drug induced liver disease)
- unpredictable
- not dose dependent
- take longer to occur
- results from an metabolic idiosyncrasy or immunological reaction
- can cause any type of liver injury
84
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what is acute liver disease
symptoms do not exceed 6 months
85
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what is chronic liver disease
symptoms persists more than 6 months
86
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What is cholestasis?
disruption of bile flow
87
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what is hepatocellular damage
injury to hepatocytes
- fatty infiltration
- inflammation
88
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can a patient have both cholestasis and hepatocellular damage?
Yes a patient may have a combination of both. Understanding damage is from cell or bile duct is important to see how sever liver disease is
89
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both cholestasis and hepatocellular damage can lead to fibrosis and cirrhosis. what are these?
fibrosis is the persistent, extensive hepatocyte damage which leads to the formation of scar tissue.
cirrhosis is the most severe form of liver damage. it is scarring of the tissue which prevents liver from carrying out normal functions
90
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what is compensated cirrhosis?
there is enough capacity to perform functions
91
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what is decompensated cirrhosis?
does not have enough capacity to perform required liver functions
92
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what are some signs and symptoms of liver disease?
jaundice
pruritus
pale stools and dark urine
spider naevi
bruising and bleeding
liver palms
finger clubbing
ascites
encephalopathy
portal hypertension
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what are the core liver blood tests?
bilirubin
alubumin
alanine aminotransferase/aspartate transferase
alkaline phosphatase
gamma-glutamyltransferase
94
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what is ascites
accumulation of fluid in the peritoneal cavity leading to swollen abdomen
- A role of albumin is keeping fluid in blood vessels
- When not enough albumin is present in blood vessels
Fluid is more likely to leak out into the tissues, particularly around the abdomen
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what is the treatment for ascites
Spironolactone (aldosterone antagonist) + furosemide (loop diuretic) and NaCl secretion.
96
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what is spontaneous bacterial peritonitis?
infection of ascitic fluid without intra- abdominal source of sepsis
97
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What is hepatic encephalopathy?
Neuropsychiatric changes including changes in mood and behaviour, confusion, delirium and coma that occurs as a result of liver failure
98
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what is the rational behind using laxative as treatment fro hepatic encephalopathy
inhibits intestinal ammonia production reducing the colonic bacterial load
99
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what is the cause of portal hypertension
there is increased resistance to flow due to:
- disruption of hepatic architecture
- compression of hepatic venules by regenerating nodules
100
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what is varices
Body forms new weak blood vessels forming of current blood vessels in aim to relive pressure. Eventually blood vessels will burst because they are very weak resulting in GI bleeding which can be vert severe due to large amount of blood