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Hyperlipidemia - Coggle Diagram
Hyperlipidemia
Hyperlipidemia
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Lipids are classified:
- TG (neutral fat)
- Phospholipids
- Cholesterol
- Lipoproteins (LDL and HDL) carry cholesterol through the blood
- LDL = atherogenic + transport cholesterol to peripheral tissue
- HDL = protective bc remove cholesterol from tissue + transport it back to the liver
5 types of lipoproteins classified according densities:
- Chylomicrons
- VLDL
- IDL
- LDL
- HDL
- Bad cholesterol =
- 60% LDL internalized by liver
- 40% LDL internalized by extra hepatic tissues
- Good cholesterol =
- From the diet or synthesized by the liver
- HDLs are poor in lipids and can remove them from peripheral tissues or atheromatous plaques in the vessels
- HDLs take those lipids back to the liver to be used
Exogenous pathway for TG and cholesterol transport:
- Involves chylomicron transport of dietary triglycerides + cholesterol from intestines -> liver
- The chylomicrons are synthesized in the wall of small intestine
- These triglyceride-rich lipoproteins transfer their triglycerides to peripheral tissues, (adipose tissue and skeletal muscle), for energy and storage
- Remnant chylomicron particles (which contain cholesterol) are then taken up by the liver and the cholesterol is used in the synthesis of VLDL or excreted in the bile
Endogenous pathway for TG and cholesterol transport:
- Liver = central site for handling of lipids: it is able to store glycerols and fats in its cells; synthesize triglycerides; and use esterified cholesterol and triglycerides to form VLDL
- Like chylomicrons, VLDLs carry their triglycerides to fat and muscle cells, where the triglycerides are removed
- The resulting IDL particles, which are reduced in triglyceride content and enriched in cholesterol, are then taken to the liver and recycled to form VLDL or converted to LDL
Hypercholesterolemia
- Increased levels of cholesterol in the blood
- Nutrition, genetics, comorbid conditions, medications, and metabolic diseases, can raise blood lipid levels
Many types of primary hypercholesterolemia have a genetic basis:
- Defective synthesis of the apolipoproteins
- Lack of lipoprotein receptors
- Defective receptors
- Defects in the handling of cholesterol in the cell that are genetically determined
Secondary causes of hypercholesterolemia include:
- Obesity with high-calorie intake
- Sedentary lifestyle
- Diabetes mellitus
Several dietary elements affect cholesterol and its lipoprotein fractions:
- Excess calorie intake
- Saturated and trans fat
- Cholesterol
<=> Excess calories consistently lower HDL and less consistently elevate LDL
The major risk factors for coronary artery disease (CAD) exclusive of LDL, cholesterol levels include:
- Cigarette
- Hypertension
- Family history of premature CAD
- Age
- An HDL cholesterol level less than 40 mg/dl
- Diabetes mellidus
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