block E - renal and hepatic Flashcards
what are the functions of the kidneys?
- regulation of H2O and inorganic ion balance
- removal of metabolic waste products from blood and excretion in urine
- removal of forign chemicals in the blood and excretion in unrine
- gluconeogenisis
- endocrine functions
what is the functional unit of the kidney?
the nephron
how many nephron are there in the 2 kidneys?
about 2.5 million
what does each nephron consist of?
- the tubular component - contains what will eventually be urine
- the vascular component - blood supply
what do the mechanisms by which the kidneys perform their functions depend on?
they depend on the relationship between the tubular component and the vascular component
what does the glomuler filtrate drain into?
bowman’s space then into the proximal convoluted tubule
what do the endothelium pores allow through?
small molecules
why do podocytes have a negative charge?
and what are they?
- it to stop proteins getting through into the tubular fluid, the basement membrane also helps with this job
- they wrap around capillaries and neighbour cells of the bowman’s capsule, they make the epithelial lining of the bowman’s capsule
what does macula densa sense GFR via?
[Na+]
what does the juxaglomuter (JG) apparatus do?
it helps regulate renal blood flow, GFR and indirectly modulates Na+ balance and systemic BP
it also has cells that secrete renin
what is GFR (glomerular filtration) controlled by?
its controlled by diameters of afferent and efferent arterioles
what is high hydrostatic pressure at golomutar capillaries due to?
short, wide afferent arteriole (low R to flow) and the long, narrow efferent arteriole (high R)
how do the kidneys control long term blood pressure?
by controlling blood volume
how do the kidneys reduce renal pressure?
they control the intrarenal redistribution of pressure and increased absorption of salt and water
what does angiotensin II do?
- causes direct constriction of renal arterioles
- stimulation of aldosterone synthesis - sodium absorption and increase in intravascular blood volume
what does decreased pressure in renal arterioles and sympathetic activity cause?
renin production and angiotensin II production
name some common liver disease conditions?
hepatitis A, B, C, D and E
what is hepatitis A?
its typically spread through contact with contaminated food and water
symptoms may clear up without treatment and recovery is a few weeks
what is hepatitis B?
it can be acute (short term) or chronic (long-term)
spread through bodily fluids
its treatable but theres no cure
what is Hepatitis C?
can be acute or chronic
often spread through bodily fluids with someone with hepatitius C
it often doesnt show symptoms in the early stages but it can lead to permenant liver damage
what is Hepatitis D?
its a serious form of hep that only develops in people with hep B
what is Hepatitis E?
its usually caused by drinking contaminated water
generally clears up in a few weeks on its own without any lasting complications
what is the early treatment of acute hep C?
interferon alpha may reduce the risk of chronic infection
what do interferons do?
they don’t directly kill viral or cancerous cells but they do bbost the immune system response stimulating T cells and other immune system cells to attack
what are some names of anti-viral drugs?
Ombitasvir with paritaprevir and ritonavir (inhibits a wide range of DNA and RNA viruses)
what does sofosbuvir do?
it inhibits the hep C virus NS5B protein
what does NAFLD stand for?
non-alcoholic fatty liver disease
what is alcoholic fatty liver disease caused by?
heavy alcohol consumption
what is NAFLD caused by?
factors other than alcohol that theyre still trying to understand
if left unmanaged, what can both types of liver disease lead to?
they can both cause liver damage, leading to cirrhosis and liver failure
what can improve symptoms and reduce your risk of complications of both types of liver disease?
diet and lifestyle changes
what can lead to fatty liver disease?
fat build-up in the liver
what does non-reversible damage of the liver cause?
- metabolism
- bile production
- cholesterol
- haematological implications
what is pioglitazone/ vit E used for?
its used by adults with advanced liver fibrosis
what does pioglitazone do?
it improves the sensitivity of hepatic tissue to insulin
theyre synthetic ligands for peroxiome proliferator-activated receptors (PPARs)
they ater the transcription of genes influencing carbohydrate and lipid metabolism resulting in changed amounts of protein synthesis and therefore metabolic changes
what vitamin is a potent antioxidant?
vit E
what are some of the autoimmune conditions involving your immune system attacking cells and your liver?
autoimmune hepatitis
primary biliary cirrhosis
primary sclerosing cholangitis
what does autoimmune hepatitus involve?
it causes your immune system to attack your liver, resulting in inflammation
if its left untreated, it can lead to cirrhosis and liver failure
what is primary billiary cirrhosis and what can it lead to if left untreatec?
it results from damage to the bile ducts in your liver and causes a build up of bile
it can lead to eventual cirrhosis and liver failure
what is Primary sclerosing cholangitis and what can it lead to?
its an inflammatory condition which causes gradual damage to your bile ducts, they eventually become blocked and cause bile to build up in your liver
can lead to cirrhosis or liver failure
what are the two treatments used to treat autoimmune liver conditons?
prenisolone and azathioprine
what is presisolone?
it increases the conc of neutrophils and decreases the levels of T and B lymphocytes, monocytes, eosinophils and basophils. it also causes a decrease in cytokine release, including decreasing in IL-2 and TNF alpha
what does azathioprine do?
its an immunosuppressant agent which acts through its effects as an antagonist of purine metabolism, resulting in the inhibition of DNA, RNA and protein synthesis
if a cancer develops somewhere else and then spreads to the liver, what is it called?
its called secondary liver cancer
what is the most common type of liver cancer?
hepatocellular carcinoma
how does hepatocellular carcinoma develop?
it tends to develop as several small spots of cancer in your liver, but it can also start as a single tumour
what other factors may contribute to the development of other cancers?
complications from other liver diseases
how do you treat liver cancer?
through surgery, chemotherapy and pharmacotherapy
what are the mechanisms of action for immune checkpoint inhibitors?
two signals are required to initiate the activaton of T cells
the first signal involves the binding of a MHC to a TCR on T-cells
the second signal arises with the binding of APC ligands, CD80 or CD86, to CD28 on t-cells
what are the names of some MABs that have been extensively studied for the treatment of cancer?
ipilimumab, tremelimumab, nivolumab, atezolizumab, durvalumab and avelumab
what is prenisolone used to treat?
a lot of autoimmune conditions
what is everrlimus?
its the brand name for mTOR (mammalian target of rapamycin) inhibitor
what is cholesostais commonly associated with?
liver cancer
what is choleostasis?
its an impairment of bile formation and/or bile flow, which may clinically present with fatigue, pruitus, dark urine, pale stools and jaundice and fat soluble vitamin deficiencies
what is cholestyramine?
its a bile acid sequestrant
what is sertraline? and what is it used to treat?
its a selecive serotonin reuptake inhibitor (SSRIs) , used as a treatment for pruritus
what are lipoprotein packages?
its lipoprotein thats in blood
what are things that build-up and contribute to liver function and cardiovascular disease?
cholesterol and lipoproteins
atherogenesis- this is the build up of plaque which leads to cardiovascular disease
sterol
where does cholesterol synthesis happen?
its synthesised primarily in the liver
occurs in the cytoplasm and ER
what is the rate limiting step of cholesterol synthesis?
the HMG-CoA reductase raction is rate limiting and highly regulated
what is the target of pharmacological intervention in cholesterol synthesis?
the HMG-CoA reductase reaction step, this enzyme os a gate keeper as it has to be active to synthesise new cholesterol, the 75% of cholesterol which is just resynthesized isn’t made this way though
what does tiparanol do?
it inhibits the last step of the choesterol synthesis pathway, it was introduces into clinical use in the mid 60s but was withdrawn from the market because of side effects, the side effects were attributed to tissue accumulation of demoterol, a substrate for the enzyme it affected
why is it important for many people to take drugs which reduce cholesterol formation?
because many of the intermediates in the pathway have biological concequences and are equally hazerdous as choleserol so if you block the pathway then you also block these intermediates from being produced
how do statins interfere with cholesterol
they interfere with the HMG-CoA reductase enzyme and as a result, the pathway downstream is blocked