Lipids Flashcards
Important function of lipids:
- Cell membrane = maintains membrane fluidity
- Thermal insulator and metabolic regulator
- Hormone synthesis
- Helps absorbs fat soluble vitamins
What are the essential fatty acids?
Linoleic and linolenic acids
What form are saturated fats in at RT?
Solid
What form are unsaturated fats in at RT?
Liquid
T/F:
Triglycerides are amphipathic (hydrophilic and hydrophobic parts)
FALSE
Triglycerides are heavily hydrophobic.
Phospholipids and cholesterol are amphipathic
What is the main function of a lipoprotein?
Main role is delivery of fuel to peripheral cells—the core is the cargo that is being transported
Size of lipoprotein correlates with the core neutral lipid content—the bigger the particle, the more content
Where are apolipoproteins located?
Primarily on the surface of the lipoprotein particles.
What is the function of an apolipoprotein?
They help maintain the structural integrity of lipoproteins and serve as ligands for cell receptors and as activators and inhibitors of the various enzymes that modify lipoprotein particles.
What is the major lipoprotein location of Apo A4?
Chylos
What is the major lipoprotein location of Apo B100?
LDL
What is the main function of LDL and where is is produced?
It reverses cholesterol transport and removed excess cholesterol from peripheral cells.
Synthesized by both the liver and the intestine.
What are chylomicrons?Where are chylomicrons produced?
A lipoprotein that transports EXOGENOUS triglycerides (the fats that we just consumed).
It has a hydrophobic core made up of 93% triglycerides and 1% cholesteryl esters.
Produced in the intestine
What is the main function of VLDL and where is is produced?
Major carrier of ENDOGENOUS triglycerides.
The hydrophobic core is 65% trig and 8% cholesteryl esters
Produced by the liver
What is the main function of LDL and where is is produced?
Involved in the ENDOGENOUS transport of cholesterol from the liver and delivers it to other organs as needed.
Produced from VLDL in blood circulation
Which lipid pathway maintains cholesterol equilibrium?
Pathway 4: reverse cholesterol transport pathway.
1 (lipid absorption), 2 (exogenous pathway), 3 (endogenous pathway) all transport dietary lipids and hepatic-derived lipids to peripheral cells.
What occurs during the lipid absorption pathway?
Pancreatic lipase converts dietary lipids into more polar compounds with amphipathic properties by cleaving off fat.
What are triglycerides converted to during lipid absorption?
monoglycerides and diglycerides
What are cholesterol esters converted to during lipid absorption?
Free cholesterol
What are phospholipids converted to during lipid absorption?
lysophospholipids
___% if of dietary triglycerides are taken up by the intestine
> 90%
Key points of the exogenous pathway
initially secrete into the lacteals > lymphatic ducts > enters the circulation via thoracic duct
ApoC2 is found on VLDL and critical for activation of LPL
In the liver the lysosomal break down the remnant particles to release free fatty acid, free cholesterol, and amino acids.
Key points of then endogenous pathway
Most that are packaged into VLDL are derived from diet after recircuation from adipose tissue
IDL taken up by liver via Apo E and LDL receptor
Trigs in IDL are removed by hepatic trig lipase which results in LDL production
Key points of the reverse cholesterol transport pathway
one major role of HDL is to maintain the equilibrium of cholesterol in peripheral cells by reverse cholesterol transport. It may remove excess cholesterol from cells by multiple pathways.
What is the acceptable mac for TC?
TC must be <190
Define Arteriosclerosis
The general name for a group of conditions that cause arteries to become thick and stiff
Define atherosclerosis
Specific type of arteriosclerosis—plaque, cholesterol and fatty substances build up in your arteries and cause them to narrow.
Plaque: This LDL is always in circulation, it will go by an endothelial cell and strip off the electrons which will oxidize the LDL molecule. This is then taken up by macrophages and gets broken down.
What labs do you perform when looking arteriosclerosis
TC, HLD-C, LDL-C, and trig
What are the two categories of hyperlipoprotenemia?
Hyperlipoproteinemias: diseases associated with elevated lipoprotein level
Hypolipoproteinemias: diseases associated with decreased lipoprotein levels
What form of hypercholesterolemia is associated with genetic abnormalities that predispose an individual to elevated cholesterol levels?
Familial hypercholesterolemia (FH)
What influences hypertriglyceridemia?
Number of hormones: insulin, glucagon, pituitary growth hormone, ACTH, thyrotropin, epinephrine, norepinephrine
____ is the presence of elevated levels of serum total cholesterol and triglycerides
Combined hyperlipidemia
Lp(a) elevation combined with elevated LSL increase the risk of ___ and ____
CHD and CVD
T/F:
Increased non-HDL-C is associated with increased CVD risk only if LDL-C levels are also elevated
FALSE:
Increased non-HDL-C is associated with increased CVD risk even if LDL-C levels are normal
What is the Friedewald calculation?
A method to measure LDL.
LDL-C = TC - HDL - Trig/5
