Lipoprotein Physiology

Question 1

Cholesterol and triglycerides are transported through lymph and blood by a sub-cellular body known as a

Answer 1

lipoprotein

Question 2

Lipids are transported through the body via lipoproteins along three major routes:

Answer 2

• exogenous pathway
• endogenous pathway
• reverse cholesterol transport

Question 3

what is the exogenous pathway

Answer 3

gathers lipids from the digestive tract and distributes them throughout the body after a meal

Question 4

what is the endogenous pathway

Answer 4

the liver builds apoliproteins and secretes them into the bloodstream – also distributes lipids throughout the body

Question 5

what is the reverse cholesterol transport

Answer 5

scavenges cholesterol from peripheral tissues and returns it to the liver

Question 6

? are synthesized by the enterocyte

Answer 6

chylomicrons

Question 7

what is inserted as a structural protein for the chylomicron during the exogenous pathway

Answer 7

ApoB-48

Question 8

HDL particles transfer ? and ? to the chylomicrons

Answer 8

ApoC-II and ApoA-V

Question 9

ApoC-II and ApoA-V allow the chylomicron to ?

Answer 9

interact with lipoprotein lipase (LPL)

Question 10

LPL on the endothelial cells of capillaries do what to the chylomicrons?

Answer 10

cleaves TGs in chylomicrons to FFAs

Question 11

after TGs are lost, the chylomicron becomes a ?

Answer 11

chylomicron remnant

Question 12

HDL also transfers ? to the chylomicron so that the chylomicron remnant can be ?

Answer 12

ApoE
cleared by the liver

Question 13

Chylomicron remnants are cleared by the liver via an ?

Answer 13

ApoE-dependent mechanism (LDL receptor)

Question 14

what is the function of the exogenous pathway

Answer 14

carry dietary lipids to most cells but especially liver

Question 15

what is the initial lipoprotein and intermediate lipoprotein of the exogenous pathway

Answer 15

chylomicron and chylomicron remnants

Question 16

VLDL is synthesized by the ?

Answer 16

liver

Question 17

VLDL contains what apoproteins

Answer 17

ApoC-II, ApoA-V and ApoB-100

Question 18

As LPL “drains” triglycerides from VLDL, it becomes ? and then ?

Answer 18

IDL and LDL

Question 19

IDL that loses TGs and becomes more and more cholesterol-rich becomes ?

Answer 19

LDL

Question 20

Liver clears IDL and LDL via the ?

Answer 20

LDL receptor on hepatocytes

Question 21

If LDL is not cleared, it can become oxidized and becomes a major risk factor for the development of

Answer 21

atherosclerosis

Question 22

HDL is synthesized by ?

Answer 22

both hepatocytes and enterocytes

Question 23

what is LCAT?

Answer 23

Lecithin-cholesterol acyltransferase

Question 24

what does LCAT do?

Answer 24

aids the process of HDL receiving cholesterol by converting free cholesterol into cholesterol esters

Question 25

HDL can help remove cholesterol from peripheral tissues via what?

Answer 25

LCAT-ApoA-1-ABC interactions

Question 26

Once hepatocytes in the liver accumulate excess cholesterol, they downregulate the ?, which reduces ?

Answer 26

LDL receptor
LDL clearance

Question 27

reducing liver cholesterol content will result in ?

Answer 27

improved clearance of IDL and LDL

Question 28

what is atherosclerosis?

Answer 28

the development of atheromas in a wide range of large and medium-sized arteries

Question 29

atherosclerosis will lead to ?

Answer 29

• endothelial injury
• accumulation of lipoproteins in the vessel wall

Question 30

what is the LDL level for low risk of cardiac risk

Answer 30

< 2.59 mmol/L

Question 31

what is the LDL level for good level to not have cardiac risk

Answer 31

2.59-3.34 mmol/L

Question 32

what is the LDL level for borderline high of cardiac risk

Answer 32

3.37-4.11

Question 33

what is the LDL level for bad level to have cardiac risk

Answer 33

> 4.14

Question 34

what is the normal range of triglycerides in a human

Answer 34

0.45-1.71 mmol/L

Question 35

what is the HDL for low risk of cardiac risk

Answer 35

> 1.55 mmol/L

Question 36

what is the HDL level for high risk of cardiac risk

Answer 36

<1.04 mmol/L

Question 37

what is normal for total cholesterol in a human

Answer 37

< 5.2 mmol/L

Question 38

what is the goal when calculating TC:HDL ratio to calculate cardiac risk from atheroschlerosis?

Answer 38

<3.5

Question 39

framingham risk score for risk (low, intermediate, and high)

Answer 39

low risk : <10 %
intermediate risk 10-20%
high risk > 20%

Question 40

what is one of the best markers of systemic inflammation as it pertains to atherosclerosis

Answer 40

hsCRP

Question 41

what is a constellation of physical exam and laboratory findings that confer a higher risk for coronary heart disease, diabetes, fatty liver, cancer

Answer 41

the metabolic syndrome

Question 42

Atherosclerosis - acute plaque changes
Fall under three general categories which are?

Answer 42

• rupture/fissuring
• erosion/ulceration
• hemorrhage into the atheroma

Question 43

plaque stability tends to be most strongly affected by?

Answer 43

• hemodynamic disturbances (increases in blood pressure)
• increased inflammation (disruption of the extracellular matrix of the atheroma)
• Factors that increase clot formation (i.e. platelet activation)

Question 44

what is atheroembolism

Answer 44

Plaque rupture can discharge atherosclerotic debris into the bloodstream, producing microemboli

Question 45

rupture, ulceration or erosion of these plaques may result in

Answer 45

stroke or MI

Question 46

what is a true aneurysm

Answer 46

an “intact” attenuated arterial wall or thinned ventricular wall of the heart

Question 47

what is an aneurysm

Answer 47

abnormal stretching (dilation or dilatation) in the wall of an artery, a vein, or the heart with a diameter that is at least 50% greater than normal

Question 48

what is a false aneurysm

Answer 48

defect in the vascular wall -> extravascular hematoma

Question 49

what is a dissection?

Answer 49

blood exits the lumen and enters the wall of the vessel