Liver Flashcards
what are the two main blood vessels bringing blood to the liver called
the hepatic artery and portal vein
what happens to the blood once it reaches the liver
The nutrient rich blood reaches the liver and hepatocytes filter and metabolises drugs, vitamins before releasing them into the systemic circulation
what is the blood vessel taking blood away from the liver called
hepatic vein
what is the main function of hepatocytes
these produce bile which is collected in the bile duct and drains towards the gall bladder where it can be secreted into the upper GI tract
the liver produces bile salts. What is the use for bile salts and why it is important?
they allow the emulsification of fats so our body can absorb fat and allow the absorption of fat soluble vitamins like vitamin A, D, E and K
where are bile salts stored, released into and what triggers this?
stored in the gall bladder and relased into the duodenum in response to food in the GI tract
another function of the liver is that it metabolises…
microbes and toxins absorbed from the gut, nutrients and drugs
how does the liver metabolise microbes
phagocytic cells which grab dead cells, bacteria and infected cells
Describe the exocrine function of the liver
-Excretes bilirubin - produced from breakdown of Hb from dead RBC
- Bile salts
-Metabolises and circulates Cholesterol – cholesterol is important for hormones and vitamin D)
Describe the synthesis function of the liver
- Produces Clotting factors
- Produces Antibodies
- Produces Albumin – albumin is a main plasma protein which Is needed to maintain osmosis in cells
how many phases of drug metabolism are there
2 phases
Phase 1 and Phase 2
what enzyme group is required for drug metabolism
Cytochrome p450
what is the purpose of phase 1
makes the molecule more water soluble
what is the purpose of phase 2
makes the molecule less active and more soluble
what is the ultimate result of drug metabolism
drugs can be filtered, do not need to be bound to plasma protein, less fat soluble, can be excreted in the kidney
what is first pass metabolism
this is when a drug passes through a specific organ and leave the organ ready for excretion or completely deactivated
what is the result of first metabolism
if a drug is subjected to first pass metabolism it means the body clears the drug quickly making the drug less effective. So some drugs may not work depending on how you administer them
which organs can first pass metabolism occur in
Liver, lung, gut and other organs
give an example of a drug that needs to be injected instead of taken orally to avoid first pass metabolism
Lidocaine
how does codeine react to first pass metabolism
codeine is converted into a more active form when it undergoes first pass metabolism in the gut and turns into morphine
what are the effects of drugs on cytochrome p450 enzymes
They can induce or inhibit the enzyme. So if drug A is ingested it can induce cyt p450 to induce metabolism of drug B which can be a downside or drug A could inhibit cyt p450 so less metabolism of drug B
explain the drug relationship between warfarin and erythromycin
- Warfarin is metabolised by the cytomchrome p450 pathway
- Erythromycin inhibits cyt p450 so warfarin less likely to be metabolised so warfarin stays in body and activity in body goes up and so does the INR (pt bleeding for longer)
- Miconazole does the same thing
what are the physical effects of liver disease
- Portal hypertension - increased pressure in portal vein caused by blood clot or scarring in liver. Often diagnosed by ascites.
- Oesophageal varices (caused by portal hypertension - increased pressure in portal vein pushes blood to surrounding blood vessels such as those in oesophagus lining. Extra blood causes varices- swollen blood vessels)
- Ascites – this is fluid retention in abdominal cavity due to portal hypertension and low albumin level due to liver disease – patient stick thin but big belly
describe the signs that someone with jaundice may have
yellow skin tone, sclera has yellow discolouration, palms have yellow tone
finger clubbing is a sign of liver disease but is it related to liver disease exclusively
No (also seen in emphysema, GIT diseases)
dupuytren’s contracture is a sign of liver disease. Describe this
contracture of the pinky and ring finger which isn’t painful but can be debilitating
gynaecomastia is a sign of liver disease describe this
this is when the sex hormones are affected by liver disease so a male body becomes more feminine like the development of breasts
sialosis is another sign of liver disease but what else can cause this
diabetes and chronic alcohol abuse
describe sialosis presentation
painless bilateral swelling of salivary gland usually in the parotid it is smooth and not bumpy (like tumour)
what can be used to test for liver disease
Liver function test which checks hormone levels like bilirubin or INR test
what are the acute causes of liver disease
alcohol, drugs and infections such as viral hepatitis
what are the chronic causes of liver disease
cirrhosis - acute causes like alcohol and infections that persist can lead to cirrhosis
describe the effect alcohol has on the liver
ethanol is metabolised into acetaldehyde in the liver which is toxic and caused inflamation and death of hepatocytes
describe the effect of overdose on drug paracetamol on the liver
- About 5% of paracetamol when taken at the safe dose (1g 4DS) will be metabolised to a toxic metabolite and then in phase 2 it will form safer metabolites
- If you exceed recommended dose you can saturate the non-toxic pathway that 95% of the paracetamol is converted to and so more will be metabolised into the toxic metabolite
- Leads to inflammation and death of hepatocytes
what effect does hepatitis infection have on the liver
causes the liver to become inflamed
which infections lead to liver disease
Hep A, B, C and E and malaria
what are signs of hep infection
Overlap with signs of gallbladder disease
- Abdominal pain in right upper quadrant where liver is
- Fever
- Jaundice
- Itchy skin
- Dark urine (bilirubin)
- Pale bowel motions that float (unabsorbed fats)
what is the route infection for Hep A
faecal-oral
what are the risk factors for hep A
poor hygiene, travel to endemic areas
what diagnosis tool is used for hep A
blood antibodies
is there a vaccine available for hep A
yes
what are the long term impacts of hep A
most recover in less than 2 months
do Hep A have carrier state
No
what is the route infection for Hep B
Infected blood, sexual intercourse, mother to newborn
what are the risk factors for hep b
unportected sex, transfusion of uncreened blood IVDA, sex workers, healthcare workers
what diagnosis tool is used for hep B
blood test - serological markers in plasma or serum detect antibodies & antigens e.g HBSAg detection means person infectious.
is vaccine available for hep b
yes
long term impact of hep b
10% develop chronic hepatitis, cirrhosis and liver failure
does hep b have a carrier state
yes
what is the rout of infection for hep c
infected blood, mother to newborn
what are the risk factors for hep c
contact with infected blood, IVDA, HIV infection
what are the diagnostic tools for hep c
blood antibodies and RNA
is there a vaccine available for hep c
No
long term impact of hep c
60% develop chronic hepatitis, cirrhosis, liver failure
does hep c have a carrier state
yes
route of infection for hep e
faecal-oral
risk factors for hep e
poor hygiene, travel to endemic areas
diagnostic tools for hep e
blood antibodies and RNA
is there a vaccine available for hep e
no
long term impact of hep e
most recover less than 2 months
carrier state for hep e
No
what is cirrhosis
scaring and fibrosis of liver so less blood flowing through the liver so less metabolism and synthesis and blood flow
explain the prevention phase of the management of liver disease
alcohol eduction and reduction is important as liver is hugely regenerative however once you past the point of regeneration it cannot be reversed, limiting over the counter paracetamol and hepatitis vaccination
describe the management of hepatitis
largely supportive, managing nutrition ass less bile salts so low fat diets and avoiding fat soluble vitamins, manage the drug choices so prescribe less than normal paracetamol, may need liver transplant
describe the exocrine function of the pancreas
- Secrete digestive enzymes produced by the acini cells – amylase, protease and lipase – secreted in response to low pH from stomach acid, fat and vagal stimulation
The enzymes are released as pro-enzymes and converted into active enzymes in the duodenum otherwise active digestive enzymes in the pancreas would cause the pancreas to digest itself
describe the endocrine function of the pancreas
Produces Insulin, glucagon and somatostatin
- Insulin and glucagon have opposing functions and are controlled by blood glucose levels
the liver, gall bladder and pancreas drain into the duodenum via what?
bile duct
what is pancreatitis
this is when obstruction of the bile duct e.g. by gallstones leads to obstruction of bile and pancreas secretions so the pro-enzymes stuck in the pancreas eventually turn to active enzymes and digest the pancreas
what are the risk factors of pancreatitis
“Trauma
Gall stones
Diabetes
Gall bladder surgery
Alcohol
Pancreatic cancer
Drugs – azathioprine “
sign and symptoms of pancreatitis
- Severe upper abdominal pain
- Radiates to the back
- Vomiting
- Weight loss
- Very unwell
- Steatorrhea
- Jaundice
- Become diabetic or worse diabetes
what is the main test for pancreatitis
serum amylase
what is the management of pancreatitis
- Mainly supportive
- Correct glucose/ electrolyte imbalance
- Antibiotics if necessary – sepsis
- Surgery to remove gallstones
how do gall stones form
“Liver secretes fats in bile including cholesterol into the bile duct In the gallbladder
If water is sucked out of the gallbladder you can get crystallisation of the cholesterol forming stones “
risk factors for gall bladder disease (gall stones)
Old Age
- Female
- High BMI
- More common in wealthier people
- High fat diet
symptoms and signs of gall stones
– Mainly asymptomatic unless they construct the bile duct
- Upper right abdomen pain
- Biliary colic: worse at meal times : pain you get when gall bladder contracts
- Nausea/vomiting
- Fever if infected
- Jaundice – because raised bilirubin levels in blood
management of gall stones
- Prevention – education of risk factors
- If you have stones then Stopping high fat diet and treat acute infection also procedure to remove stones
