15. Lipid Metabolism, Pathophysiology and Lab Tests

Question 1

3 components of a chylomicron

Answer 1

• Cholesterol
• Phospholipids
• Protein (coat)

Question 2

Effect of insulin on lipolysis?

Answer 2

Deceases lipolysis by reducing conversion of fat cell lipid stores into blood fatty acids

Question 3

What is linolenic acid an example of?

Answer 3

Polyunsaturated FA

Question 4

What is analyzed in the precipitation separation method for HDL measurement?

Answer 4

The SUPERNATANT is analyzed for HDL

Question 5

More common method of HDL measurement?

Answer 5

Homogenous enzymatic colorimetric mehod

Question 6

Effect of insulin on lipid synthesis?

Answer 6

Increases lipid synthesis (forces fat cells to take in blood lipid => converted to trigs)

Question 7

Cause of turbid bottom layer

Answer 7

VLDL

Question 8

Which apolipoprotein to test in the lab for HDL?

Answer 8

A1

Question 9

When chyme enters duodenum, it triggers a hormonal signal called _________

Answer 9

Cholecystokinin

Question 10

Causes a cream layer on top of plasma after overnight refrigeration

Answer 10

Chylomicrons (lowest density)

Question 11

Main function of apolipoproteins?

Answer 11

Direct lipids to correct target

Question 12

What does a turbid sample indicate?

Answer 12

Trig levels > 4 mmol/L

Question 13

Liver synthesis of trigs - 2 sources?

Answer 13

• FAs in adipose tissue

- Carbs from diet

Question 14

Triglycerides RI

Answer 14

< 1.70 mmol/L

Question 15

Hormone sensitive lipase activity is promoted by ________ and inhibited by _________

Answer 15

Promote - growth hormone

Inhibit - insulin

Question 16

What is familial hypecholesterolemia? Consequences?

Answer 16

Defective LDL receptor = no LDL internalization

Leads to atherosclerotic plaque formation

Question 17

4 functions of cholesterol

Answer 17

1. Cell membranes
2. Precursor of bile acids
3. Precursor for all steroid hormones
4. Vitamin D

Question 18

____________ cannot be synthesized in the human body

Answer 18

Essential fatty acids

Question 19

Main function of trigs?

Answer 19

Provide energy for cells and component of cell membranes

Question 20

4 forms FAs can exist as

Answer 20

• Free fatty acids
• Triglycerides
• Phospholipids
• Cholesterol esters

Question 21

What do patients w/ primary hyperlipidemia develop

Answer 21

Xanthomas

Question 22

Function of cholecystokinin

Answer 22

Triggers gall bladder release of bile into duodenum

Question 23

Which apolipoprotein to test in the lab for LDL?

Answer 23

B100

Question 24

Difference between abetalipoproteinemia and dysbetalipoproteinemia

Answer 24

Abeta- = Defective apoprotein B synthesis

Dysbea- = defect in Apo-E synthesis

Question 25

4 major lipids present in plasma

Answer 25

- Fatty acids - Triglycerides - Phospholipids - Cholesterol

Question 26

6 functions of lipids

Answer 26

1. Storage/source of energy 2. Cell membrane structure 3. Chemical messengers 4. Vitamins 5. Shock absorber 6. Insulation

Question 27

What does a decrease of Apo C2 lead to?

Answer 27

Increased CMs and trigs

Question 28

Reason for lipid profile with elevated trigs but normal total chol?

Answer 28

Patient didn't fast = need recollection

Question 29

Molecule that determines how trigs are used

Answer 29

Lipoprotein lipase

Question 30

What makes lipids soluble in blood?

Answer 30

Lipids are combined with protein (lipoprotein)

Question 31

2 interfering agents w/ cholesterol measurement?

Answer 31

Reducing agents (vitamin C, bilirubin)

Question 32

3 conditions where fecal fat is elevated

Answer 32

- Chronic pancreatitis - Celiac disease - Short bowel syndrome

Question 33

5 drugs used to manage lipid disorders

Answer 33

- statins - fibrate - bile acid binding resins - ezetimibe - nicotinic acid

Question 34

When is it not possible to use the LDL formula

Answer 34

When trigs > 4.5 mmol/L

Question 35

2 functions of phospholipids

Answer 35

- Cell membrane | - Lipoprotein outer shell

Question 36

Cause of primary hyperlipidemia?

Answer 36

Absent/defective LPL, LDL receptors or apolipoproteins

Question 37

Function of Apo C2

Answer 37

- Activates lipoprotein lipase (LPL) | - Stored on HDL for transfer to chylomicrons and VLDL