block 3 lecture 8 bile and plasma lipids Flashcards
what is a phospholipid?
lipid based molecule with a polar head and a hydrophobic tail
what is metabolism?
chemical reactions involved in maintaining an organism
what is glycolysis?
glucose is converted to pyruvate
what is gluconeogenesis?
conversion of pyruvate to glucos
what is glycogenolysis?
glycogen is converted to glucose
what is lipoysis?
conversion of lipid to free fatty acids
what is a ketone body?
lipid based energy molecule
what is cholesterol important for?
hormone synthesis and the lipid bilayer
how are hydrophobic lipid molecules converted into amphipathis
adding phosphate groups
what is the structure of the amphipathic lipids?
hydrophobic on the outside hydrophobic on the inside
what are lipoproteins for?
substrates for energy metabolism essential components for cells precursors for hormones lipid soluble vitamins precursors for bile acids
what are the two lipid transport pathways?
exogenous and endogenous
what happens in the exogenous pathway?
take in lipid in the diet and pass into your blood stream as clarithromycins
what happens in the endogenous pathway?
fats produced in the liver are altered around the body into different types of lipoprotein
what are chylomicfrons predominantly made up of?
triglyceride
what is the composition of VLDL?
lots of triglyceride
where are chycomocrons synthesised?
small intestines
what are chylomicrons synthesised from?
trigycerides, phospholipids and apoB
where do the chylomicrons go after they have been in the small intesting?
released in the lymph system
how do the chylomicrons get into the blood stream?
thoracic duct
what happens to the chylomicrons in the blood?
metabolised by lipoprotein lipase
what does lipoprotein lipase break down triglycerides into in the blood?
fatty acid and glycerol
what happens to the chylomicron remnant in the blood
picked up by apoE receptors on the liver which can process it into something else
what is the lipoprotein lipase expression linked to?
insulin
what happens if there is a mutation in liporpotein lipase?
lots of chylomicrons
what is liporpotein lipase bound to?
surface of vascular endothelial cells
where do you find lots of chylomicrons?
adipose tissue/skeletal muscle/myocardium and mammary glands
in the endogenous pathway where are VLDLs produced?
liver
what are the VLDLOs in the endogenous pathway broken down into in the blood?
broken down into intermediate density lipoproteins
what happens to the intermediate density lipoproteins in the endogenous pathway?
may return to the liver or be broken down into LDLs
what happens to the LDLs produced from VLDLs in the endogenous pathway?
transported back to the liver or enter peripheral tissues
what is high LDL associated with?
greater risk of CHD
why is high LDL associated with thrombotic events?
can be oxidised which activates platelets
what happens after perippheral tissue pick up LDL?
LDL is internalised by clathrin pits
what happens to the clathrin pit vescile?
becomes declathrinated
what does declathrination of the vescile change?
pH
what does the decrease in pH in the vesicle do?
causes the destruction of LDLs into amino acids/fatty acids/cholesterol
what is the route in reverse cholesterol transport?
peripheral tissue to the blood to the liver
what do abnormalities in serum lipoprotein profile suggest?
problems in metabolism/liver function/renal function
what contributes to levels of HDL/LDL?
diet/excersize/body fat/type 2 diabetes/genetics
how does familial hypercholesterolemia present?
deposits under the skin
what are patients with familial hypercholesterolemia at risk to?
cardiovascular disease
what do statins do?
activate HMG Co A reductase
elevate HDLs
what can hyperlipidemia be caused by?
hormones/metabolic disorders/renal dysfunction
how is white adipose tissue produced?
glucose - glycerol - fat
VLDLs/chylomicrons broken down in the body by LPLs
what is the breakdown of fat stores driven by?
adrenaline
noradrenaline
glucagon
what is fat broken down into in prolonged starvation?
ketone bodies
what are the two main ketone bodies?
acetoacetate
3 hydroxybutrate
when do you find high ketone bodies?
prolonged starvation
diabetes
what is the difference between white and brown adipose tissue?
white: 1 droplet
brown: lots of little droplets, mitochondria have thermogenin which produces heat
what produces heat?
brown adipose tissue
how is heamoglobin broken down?
haemoglobin converted to heam and globin
haem converted to biliverdin
biliverdin converted to bilirubin
what happens to bilirubin?
protein bound to albumin in blood and is transported to the liver
what happens to bilirubin in th liver?
undergoes conjugation with glucorinic acid
why is bilirubin conjugated?
make it more soluble in water
what happens to the conjugated bilirubin?
excreted in the bile duct to the small intestine
what happens to the conjugated bilirubin in the intestine?
converted to urobilinogen and moved to the kidneys or removed in fecaes
what might you see if someone has a liver problem?
jaundice
