Lipid and Lipoprotein Metabolism

Question 1

What are the clinically important lipids?

Answer 1

1. Cholesterol 2. Trigylercides (phospholipids and glycolipids also exist).

Question 2

Fats are INSOLUBLE in…

Answer 2

water and plasma

Question 3

What are some examples of the functions of lipids?

Answer 3

Steroid hormone precuros, bile salt precursor, cell membrane components, provides energy and metabolic fuel, insulation, provides maturity to fetal lung as pulmonary surfactant.

Question 4

What is cholesterol an essential component of?

Answer 4

cell membranes

Question 5

What is cholesterol a precursor for?

Answer 5

steroid hormones; bile salt synthesis

Question 6

How is lipid stored in adipose tissues? (what form?)

Answer 6

Triglycerides

Question 7

What are some functions of trigylcerides?

Answer 7

main storage form in man, cushions vital organs, provides insulation, acts as metabolic fuel and energy source.

Question 8

What do phospholipids “act as”?

Answer 8

biologic detergents, and stabilizers.

Question 9

What is the chemical structure of phospholipids?

Answer 9

Hydrophilic head, and hydrophobic tail

Question 10

What are some functions of phospholipids in the body?

Answer 10

surfactant in lungs (phosphatidylcholine), and protects against premature infants. It also stabilizes cell membranes.

Question 11

What do glycolipids contain?

Answer 11

contain carbohydrate

Question 12

What is the function of glycolipids?

Answer 12

major lipid of cell membranes in the brain and CNS (gangliosides and sphingomyelin).

Question 13

What are the sources of lipids?

Answer 13

1)exogenous (dietary intake, 300-500 mg chol/day), chylomicrons. 2) endogenous (synthesized by liver, 1500 mg chol/day, VLDL)

Question 14

How do lipids get packaged to travel through physiological fluids?

Answer 14

lipoproteins

Question 15

What are the specific proteins that are on lipoproteins surface?

Answer 15

apolipoproteins

Question 16

apolipoproteins do what?

Answer 16

activate metabolic enzymes, maintain structural integrity of lipoprotein, facilitate uptake of lipoprotien into cells.

Question 17

What does research show about apolipoproteins?

Answer 17

abnormalities may lead to abnormal lipid metabolism and metabolic disorders such as: atherosclerorsis, CV disease, stroke, Alz. disease

Question 18

Lipoprotein classifications:

Answer 18

chylomicrons, VLDL, LDL, HDL. They are classified based on relative densities. Chylos float, HDLs sink!

Question 19

Which of the following lipoproteins carries the highest percentage of cholesterol?

Answer 19

LDLs

Question 20

Which of the following lipoproteins carries the highest percentage of triglycerides?

Answer 20

BOTH chylomicrons (carries exogenous, found in non-fasting state) and VLDL (carries endogenous, found in fasting state )

Question 21

What causes the plasma to appear lipemic?

Answer 21

VLDL, will make plasma look hazy

Question 22

Where does LDL deposit cholesterol?

Answer 22

plaques

Question 23

Increased LDLc increases risk of…

Answer 23

CHD

Question 24

Which of the following lipoproteins carries the highest percentage of protein?

Answer 24

HDL

Question 25

Which of the following lipoproteins carries the highest percentage of phospholipid?

Answer 25

HDL

Question 26

What patient preparations are necessary for sample collection of a lipid panel?

Answer 26

12-14 hour overnight fast to clear system of chylomicrons. Collect in GLYCEROL-FREE tube.

Question 27

What are factors that affect cholesterol levels? (see slides 25 and 26 of lipids for EXACT info)

Answer 27

age (increases), sex (different trends for female vs male--see chart), menustration (peaking effect), fasting (negligible), stress (increases), time of specimen (variable), hemolysis (negligible)

Question 28

What is a lipid profile?

Answer 28

Used to assess patient risk of CHD. Gives you | 1. total cholesterol 2. total triglyceride 3. HDL 4. LDL 5. Cholesterol:HDL ratio

Question 29

How do you calculate LDLc?

Answer 29

Friedwald equation. ``` LDLc= Total Cholesterol -HDL-VLDL. VLDL= tri-g's/5 ```

Question 30

what should your total cholesterol be?

Answer 30

less than 200

Question 31

what should your HDL be?

Answer 31

35-55 (you want it high)

Question 32

what should your LDL be?

Answer 32

less than 130

Question 33

what should your tri-g's be?

Answer 33

less than 150

Question 34

What are risk factors for CHD?

Answer 34

male older than 45 (females older than 55), fam hx, smoking, hypercholestermia: LDL more than 160 with less than 2 risk factors or LDL 130-159 with more than 2 risk factors, obesity sedentary lifestyle, hypertension, stress, diabetes

Question 35

What are some causes of secondary hyperlipidemia and dyslipprotenemia?

Answer 35

drugs, alcohol, obesity, DM, hypopituitarism, Hypothryroidism, pregnancy, lipid storage diseases, renal disease, heptic disease, acute or transient conditions, anorexia nervosa, SLE, Gout

Question 36

What is Tangier's disease?

Answer 36

increased catabolism of the HDL molecule. Results in severely decreased or absent HDL with accumulation/deposits of cholesterol in tissues and vital organs. You get a big liver, increased risk of CHD, and plasma cholesterol is low

Question 37

What are lipid storage disorders

Answer 37

critical lysosomal enzyme needed for lipid catabolism is decreased, absent, or defective. Results in accumulation of lipid in lyzosomes of vital organs and tissues. Often fatal at early age