Lipid Testing and Cardiac Risk Assessment

Question 1

Types of Lipids

Answer 1

Fatty Acids
Glycerol Esters
Triglycerides
Phospholipids

Question 2

Fatty Acids Info

Answer 2

Short, medium, & long chains linear molecules that are major constituents of triglycerides and phospholipids (Saturated, Monounsaturated, Polyunsaturated)
Found in cell membranes
Components of hormones and vitamins

Question 3

Glycerol Esters Info

Answer 3

Triglycerids: Glycerol ester comprised of glycerol and 3 fatty acid molecules
Phosphoglycerides: Glycerol esters/phosphoric acid group and 3 fatty acid molecules
- Lecithin: cholin molecule
- Cardiolipins

Question 4

Triglycerides Info

Answer 4

Form oils at room temperature if plant based, solid structure when animal based
95% of fats shored in adipose tissues
Transported in body as chylomicrons and very low density lipoproteins (VLDL)
Metabolism involves releasing fatty acids to the cells for energy, then recycling the glycerol into triglycerides
Lipase, lipprotein lipase, epinephrine, and cortisol breakdown triglycerides

Question 5

Phospholipids Info

Answer 5

3rd position on the glycerol backbone contains a phospholipid head
Phospholipid head group determines the phospholipid type
Are a major constituent of cell membranes and outer shells of lipoprotein molecules

Question 6

Phosphatidylcholine

Answer 6

Lecithin
Most common phospholipid
Has a choline head

Question 7

Amphipathic lipid molecules

Answer 7

Found on surface of lipid layers
Hydrophilic head faces outward
Fatty acid chains face inward

Question 8

Sphingosine derivatives

Answer 8

Sphingomyelin
Important for normal lung function along with lecithin
Keeps alveoli distended

Question 9

Cholesterol Info

Answer 9

Unsaturated sterol alcohol found exclusively in animals
Synthesized from acetyl-CoA in microsomal and cystosolic compartments of cells
Amphpathic lipid found on surface of lipid layers along with phospholipids
Also exists in highly polar esterified form known as Cholerteryl ester
Not readily catabolized by most cells and does not serve as energy source for body
Elevations correlate with coronary artery disease from plaque formation

Question 10

Cholesterol Functions

Answer 10

Cell membrane structural component
Bile acid precursor
Steroid hormone precursor

Question 11

Sources of Cholesterol

Answer 11

Exogenous
Endogenous
- 70% in skin, adipose tissue and muscle cells
- 30% is in transport in form of lipoproteins (LDL & HDL)

Question 12

Lipoproteins info

Answer 12

Lipids packaged in a micelle of cholesterol, triglyceride, phospholipids and protein

Question 13

HDL

Answer 13

High density lipoprotein
Prefer to see this in high numbers

Question 14

LDL

Answer 14

Low density lipoprotein
Not as good at carrying cholesterol

Question 15

IDL

Answer 15

Intermediate density lipoprotein (VLDL remnants)
- Normally short lived form in conversion of VLDL to LDL
- In type 3 hyperlipoproteinemia, IDL are detected
- Rare inborn error in which abnormal apo E delays clearance

Question 16

VLDL

Answer 16

Very low density lipoprotein

Question 17

Chylomicrons

Answer 17

Tons of lipids and triglycerides
Very little protein

Question 18

Lipoprotein Structure

Answer 18

Spherical structure of lipids and proteins (called apolipoproteins)
Role is to transport lipids to and from cells to liver and dietary lipids from intestines

Question 19

Amphipathetic Cholesterol and phospholipids

Answer 19

On surface as a monolayer

Question 20

Triglycerides and cholesterol lipids

Answer 20

Polar
Inside core

Question 21

Apolipoproteins

Answer 21

Protein component of lipoproteins located on the surface of the lipoprotein particle
Protein composition differs from one lipoprotein class to another

Question 22

Functions of Apolipoproteins

Answer 22

Make hydrophobic lipids soluble in blood for transport
Activate enzymes involved in lipid metabolism
Maintain structural integrity of lipid/protein complex
Deliver lipids to cells via recognition of cell surface receptors

Question 23

Apolipoprotein A-1

Answer 23

Major constituent of HDL
Activates lecithin-cholesterol acyltransferase (LCAT) which catalyzes the formation of cholesterol esters
Higher A1 = lower plaque formation

Question 24

Apolipoprotein B

Answer 24

Apo B-100
Major component of LDL, VLDL, and chylomicrons
Binds to LDL receptors

Question 25

Apo B-48

Answer 25

Found only in chylomicrons

Question 26

Apolipoprotein C

Answer 26

Apo C-I, C-II, C-III all found in chylomicrobs as well as VLDL and HDL (in smaller amounts)
Activates lipoprotein lipase (LPL) which breaks down triglycerides at the cellular level for metabolism and storage

Question 27

Apolipoprotein E

Answer 27

Found in VLDL, IDL, and HDL, chylomicrons
Regulates receptor-mediated uptake and clearance of lipids and stimulates lipolysis
LDL receptor ligand

Question 28

Apolipoprotein (a)

Answer 28

Lipid similar to LDL with an abnormal inherited protein designated as (a) attached to LDL
Can have increased LDL and Lp (a) can occur concurrently
Regulates the expression of Lp(a) in liver
Increased levels have a high risk associated with premature coronary artery disease and stroke
Migrates in the “fast” pre-beta region of the lipoprotein electrophoresis

Question 29

Tongue gland

Answer 29

Produces lipase that beings to break down fat

Question 30

Bile production

Answer 30

By liver and aids in digestion
Composed of 97% water, 0.7% bile, 0.2% bilirubin, 0.51% fats, and 200 mEq/L inorganic salts

Question 31

Bile salts and Pancreatic Lipase

Answer 31

Breakdown and emulsify fat

Question 32

LDL calculation

Answer 32

LDL = Total Cholesterol - (HDL + (Triglycerides/5))