بخشی از پاورپوینت
--- پاورپوینت شامل تصاویر میباشد ----
اسلاید 1 :
lIntroduction
¡Used to prevent or slow progression of atherosclerosis to reduce the risk of coronary artery disease and prolong life
lCholesterol
¡Advantages
lServes as a component of cell membranes and intracellular organelle membranes
lIs involved in the synthesis of certain hormones including estrogen, progesterone, testosterone, adrenal corticosteroids
lNeeded for the synthesis of bile salts which are needed for digestion and absorption of fats.
اسلاید 2 :
lCholesterol
¡Advantages
lIs deposited in the stratum corneum of the skin to help ↓ evaporation of water and create impermeability to water soluble compounds (helps keep moisture in skin)
¡Origin
lIs synthesized in the liver. Acetyl CoA is converted to mevalonic acid and ultimately to cholesterol by hydroxymethyl glutaryl coenzyme A (HMG-CoA) reductase.
اسلاید 3 :
lCholesterol
¡Origin
lEndogenous synthesis of cholesterol increases at night
lAn increase in dietary cholesterol produces only a small ↑ in blood levels of cholesterol because ingestion inhibits endogenous synthesis
lDietary saturated fats ↑ blood cholesterol levels because they are converted to cholesterol in the body.
اسلاید 4 :
lLipoproteins
¡Serve as carriers for transporting lipids (cholesterol and triglycerides) in the blood.
¡Apolipoproteins
lEmbedded in the lipoprotein shell
lThree functions
- 1. Serve as recognition sites for cell-surface receptors; allowing cells to bind and ingest the lipoprotein.
- 2. Activate enzymes that will metabolize the lipoprotein
- 3. ↑ structural stability of the lipoprotein
اسلاید 5 :
lLipoproteins
¡Apolipoproteins
lAll lipoproteins that deliver lipids to peripheral tissues (nonhepatic tissues) contain apolipoprotein B-100 (Ex: VLDL, LDL)
lAll lipoproteins that transport lipids from peripheral tissues back to the liver contain apolipoprotein A-I (Ex: HDL)
اسلاید 6 :
lLipoproteins
¡Lipoproteins of importance
lVLDL (very low density lipoprotein)
- Contain triglycerides (TGs) and some cholesterol
- Account for nearly all TGs in the blood
- Contain B-100
- Deliver triglycerides from the liver to adipose tissues and muscles.
اسلاید 7 :
lLipoproteins
¡Lipoproteins of importance
lVLDL (very low density lipoprotein)
- Remnants of hydrolysis are IDL (intermediate density lipoproteins), which can be transported to liver or converted to LDL
اسلاید 8 :
lLipoproteins
¡Lipoproteins of importance
lLDL (low density lipoprotein)
- “Bad cholesterol”
- Contain cholesterol
- Account for 60-70% of cholesterol in the blood
- Contains B-100
- Delivers cholesterol to peripheral tissues
اسلاید 9 :
lLipoproteins
¡Lipoproteins of importance
lLDL (low density lipoprotein)
- Formed from IDL, the remnants of VLDL
- Makes the greatest contribution to coronary atherosclerosis
Oxidized LDL contributes to atherosclerotic plaque
- Removed from plasma via endocytosis by liver converting it to bile acids excreted in GI
اسلاید 10 :
lLipoproteins
¡Lipoproteins of importance
lHDL (high density lipoprotein)
- “Good cholesterol”
- Contain cholesterol
- Account for 20-30% of cholesterol in the blood
- Some contain Apo A-I and Apo A-II
- Apo A-I is cardioprotective
- Transports cholesterol from the peripheral tissues back to the liver – promotes cholesterol removal
- Antiatherogenic