Liver Anatomy & Functions Flashcards
How much cardiac output does the liver produce
25%
Name the 4 lobes
Major- left and right
Minor - caudate and quadrate
List the main ducts in the liver
Common hepatic
Cystic
From gallbladder
- common bile duct/ joining pancreatic duct at hepatipancreatic ampulla
Where do the common bile duct and pancreatic duct join
Hepatopancreatic ampulla
Name the capsule of connective tissue surrounding the liver
Glisson’s capsule
What do the hepatic artery and portal vein supply
Artery- oxygen rich
Vein- nutrient rich
What does the celiac artery filter blood from
Stomach spleen and pancreas
What does the superior mesentric artery collect blood from
Pancreas
SI
Colon
What does the inferior mesentric artery collect blood from
Colon
Where does the portal vein deposit its contents
Sinusoids
Describe the structure of liver lobules
Hexagonal structure containing hepatocytes
Radiate outward from central vein
At each six corners is a portal triad
Contains sinusoids
Other terms for hepatic cells
Hepatocytes
Function of sinusoids
Specialised capillaries large and fenestrated
Function of kupffer cells
Fixed macrophages with phagocytic function
Function of stellate cells
Storage of vit A, when activated become fibrous
Function of basolateral membrane
Between hepatocytes and space of disse
Has microvilli
Function of apical membrane
Makeup bile canaliculi
Where is oxygen highest and metabolic pathways that occur
Periportal cells
Gluconeogenesis/ b oxidation
Nutrient/ oxygen
Where is o2 supply the lowest and metabolic pathways that occur
Central vein
Glycolysis
Lipogenesis
B catenin/ signalling
Liver injury at periportal cells
Autoimmune hep
Iron overload injury
Billiary cirhosis
Liver injury at central vein
Nafld
Drug alcohol toxicity
Parasite infection fibrosis
Describe the route of bile
Bile canaliculi to bile duct
Then common hepatic duct
Function of bile
Emulsify fats
What is stored in gallbladder and how is it stimulated
Bile not immediately needed for digestion, stimulated by CCK & secretin
What are bile acids derived from
Cholestrol
Mechanism of Action of bile- how does it work
In conjugation to taurine and glycine, increases polarity of molecules
Function of sinusoidql transporter ntcp
Bile acid transporter, symport with sodium
Function of oatp sinusoidal transporter
Organic anion transporter protein
Into hepatocyte and blood
Function of oct
Into hepatocyte and blood
Function of mrp4
Transport drug metabolite back into blood
Function of biliary transporter mrp2
Bilirubin transported to bile
Function of biliary transporter abcg
Cholestrol
Function of biliary transporter mdr3
Pc
Function of biliary transporter bsep
Bile salts
Function of biliary transporter mdr1
Drug and metabolites
Function of biliary transporter bcrp
Steroid derivatives
Function of mdr1, abcb1 (p gylcoprotein) in the body
Found in liver gi tract kidneys and brain
Pump materials out of brain,
Activity can be both induced and inhibitted
Enzyme which activates bilirubin
Uridine glucournayl transferase
Methods of excretion for bile
Feces
Urine
Enterohepatic circulation
Functions of liver
Metabolic
Synthesis
Breakdown
Storage of vitamins
Excretion of waste products from blood stream to bile
Carbohydrate and lipid metabolism
Gluconeogenesis
Glycogenolysis
Glycogenesis
Cholestrol synthesis
Lipogenesis
At basal state what happens to blood sugar levels
Decreased glucose and insulin
Increased glucagon
At starved state what happens to blood sugar levels
Decreased insulin and glucose
Increased glucagon
Acetyl CoA supply straight to the brain
Hormones involved in glycogen mobilisation
Insulin
Glucagon
Adrenaline
Target organs involved in glycogen mobilisation
Liver and muscle
Key enzymes regulated from glycogen mobilisation
Glyogen synthase and phosphorylase
Function of glycogen phosphorylase
Removal of glucose residues
How is glycogen phosphorylase controlled
Kinase - active
Phosphatase- inactive
Why is glycogen synthase switched off
Stop a futile cycle
Function of glycogen synthase
Regulate synthesis of glycogen
Why do we need protein synthesis
Amino acids
Albumin
A/b globulins
Tranferrin
Hormones
Why do we need aa for breakdown
Bd insulin and other hormones
Amino acid metabolism
Ammonia to urea
Drug metabolism
Enzymes used in amino acid formation
Transaminase
Aminotransferase
Function if glutamate dehydrogenase
Release ammonia
And generate nadph
Enzyme for glutamine synthesis
Glutamine synthetase
Enzyme for glutamine hydrolysis
Glutaminase
What can increased urea levels cause
Cerebral oedema
Function of orthinine transcarbamylase
Turns carbsmoyl phosphate and orthinie into citrulline
Effect of OTc deficiency in urea cycle
Build up of toxic ammonia levels= hyperammonemia
Definition of drug metabolism
Process by which biochemical reactions alter drugs into the body
Another term for drug metabolism
Drug biotransformation
What can cause a loss of pharma activity in liver
Change in structure
What are pro drugs and toxic metabolites a product of
Change ins structure
Why are substances excreted by liver
Lipophillic xenobiotics are not elimintaed efficiently by kidney
What does the process of biotransformation do
Parent drug turned imore polar
Difference between phase 1 and phase 2 reactions
Phase 1 unmasks chemical reactive functional group
phase 2 conjugates endogenous molecule onto functional group
Examples of phase 1 reactions
Oxidation
Reduction hydrolysis
Examples of phase 2 reaction
Sulphation
Glucuronidation
Acetylation
Methylation
Describe cytochrome p450
Haem proteins that catalyse monooxygenase reactions
What does cytochrome p450 play an important role in
Primary mediators of phase 1 reactions
Requirements for p450 catalytic cycle
Molecular oxygen
Nadph
Lipid- membrane bound endoplasmic reticulum
How do we classify isoforms of cyp p450
Homology of primary amino acid sequence
Why are cytochromes considered first defence against xenobiotics
High catalytic versatility
Broad substrate specificity
What do the different overlapping substrates cause in CYP
Different rates of metabolism
In a phase two reaction, what will all enzymes be
Transferases
What is the effect of phase 11 metabolism
More polar = more water soluble
In a glucuronidation reaction what are the reactants
Glucuronic acid WITH
OH
COOH
NH2
SH
Forming an amide ester or thiol bond
In a glutathione reaction, what does glutathione perixidase convert glutathione into
Reduced to oxidised
In a glutathione reaction, what does glutathione reductase convert glutathione into
Oxidised to reduced
In general terms, explain the steps of phase 1 and phase 11 reactions
Drug ——derivative———conjugate
What will drug metabolism affect
Drug concentration
What useful parameters are used for pharmacokinetics
Half life
Area under the curve
Definition of half life
Time taken for concentration of drug to fall by half
Definition of cmax
Highest concentration of drug in blood
Definition if cmin
Lowest concentration of drug in blood
Factors affecting drug metabolism
Disease-liver
Genetic factors-
Polymorphic distribution
Definition of poor metaboliser
Lackijg active gene allele
Definition of intermediate metaboliser
Homozygous for 2 reduced activity gene alleles
OR
Heterozygous for inactive allele
Definition for extensive metaboliser
Normal complemenet of 2 fully active gene alleles
Expect response to standard dose
Definition of ultrarapid metaboliser
More than 2 copies of active gene alleles
Three types of activation
Induction
Auto induction
Heteroinduction
Concerns regarding clinical implications of cyp induction
Reduction in pharma effect
Induction leads to toxicity
3 types of inhibitors
Competitors
Non competitive inhibitors
Irreversible inhibitors
Effect of comp inhibitor
Most common
Como for active site
Effect of non comp inhib
Form inactive intermediate with enzyme = decreased enzyme activity
Effect of irreversible inhib
Substrate inactivates enzyme
Time dependent loss of enzyme activity
Aka suicide inhibitors
What is the effect of administering a cyp inhihitor with a drug
Slower rate of clearance
Propranolol and metoprolol can have interaction with:
Fluoxetine
Paroxetine
Antidepressants
Quinine
Cyp2d6 inhibitors
What can st johns wart interact with
Enzyme inducers
Inducing hepatic cyt p450 and intestinal p glycoproteins
Increased blood levels of calcium and statins naturally is due to
Grapefruit juice containing furancoumarins which inhibit cyp3a4 in gut wall and liver
Steatosis
Fatty liver due to alcohol
Nonalcoholic fatty liver due to diabetes
Cholestasis
Blockage of bile flow leading to jaundice
Cirrhosis
Loss of lobular structure
Causes of cirhosis
Alcohol abuse
Hep b c
Errors of metab
Adverse drug reaction
Symtoms of cirrhosis
Blockage of venous flow leading to hypertension
Biliary obstruction leading to jaundice
Liver cell failure - decreased metabolism
Symptoms of portal hypertension
Hypersplenism
Neutropenia
Thrombocytopenia
Marked ascites
List Treatment of cirrhosis
Prevention of fibrosis
Limit fluid retention/encephalopathy
Avoid alcohol
Ascites if present reduce salt intake and diuretics
Causes of hepatitis
Liver inflammation leading to celullar necrosis
Due to viral/alcohol/drugs
Symptoms of acute viral hepatitis
Less than 6 months
Nausea/vomiting
Increased bilirubin
Symptoms of chronic viral hep
More than 6 months
Asymptomatic
Fever/fatigue
Treatment of viral hepatitis
Rest
Low fat diet
No alcohol
Avoid contact
Acute alcoholic hepatitis
Hep inflammation and necrosis
Similer symp to HAV
No alcohol
Treatment for Drug induced hep mimick acute viral hep
Drug withdrawal
Gallbladder disorder
Treatment methods
Cholangitis
Bile duct inflamed
Vomiting and pain
Antibacterial/IV fluids
Surgery
Cholecystisis
Different types
With treatment methods
Inflammation of gall bladder
Acute and chronic
Retained bile in gallbladder
Pain/jaundice
Opioid analgesics
Antibac drugs
Overdose of paracetamol can lead ti
Hepatotoxicity
Explain the effect of taking paracetamol overdose
Glucuronide saturation = sulphate/gsh conjugate depletion
=== increased toxicity’s
List sinusoidal transporters
Ntcp
Oatp
Oct
Mrp4
List biliary transporters
MRP2
Abcg 5/8
Mdr3
Bsep
Mdr1
Bcrp
What enzyme activates glycogen synthase
Protein kinase a
What stops glycogen syntahse
Phosphoproteun phosphatase 1
What can CYP450 be also known as
Mixed function oxidase
Requirements for mixed function oxidase
Molecular oxygen
Nadph
Lipid (membrane bound endoplasmic reticulum)