IHD lipids final

Question 1

What are the two main lipids in human physiology?

Answer 1

Cholesterol and triglycerides.

Question 2

Main function of cholesterol?

Answer 2

Structural building molecule.

Question 3

Main function of triglycerides?

Answer 3

Energy storage (metabolic fuel).

Question 4

What type of molecule is cholesterol?

Answer 4

A steroid molecule composed of four fused hydrocarbon rings.

Question 5

Why is cholesterol hydrophobic?

Answer 5

Its structure is mostly non‑polar hydrocarbon rings.

Question 6

Why can cholesterol not circulate freely in blood?

Answer 6

Plasma is water‑based and cholesterol is water‑insoluble.

Question 7

How does the body transport cholesterol in blood?

Answer 7

Using lipoproteins.

Question 8

Key idea about cholesterol and disease?

Answer 8

Disease depends on transport and amount, not cholesterol itself.

Question 9

Important roles of cholesterol in the body?

Answer 9

Cell membranes, steroid hormones, vitamin D, and bile acids.

Question 10

What percentage of cholesterol is made by the liver?

Answer 10

About 80%.

Question 11

What percentage comes from diet?

Answer 11

About 20%.

Question 12

Why do statins work well?

Answer 12

They block hepatic cholesterol production.

Question 13

What forms of fat enter the intestine from diet?

Answer 13

Cholesterol esters and triglycerides.

Question 14

What enzyme frees cholesterol from cholesterol esters?

Answer 14

Cholesterol esterase.

Question 15

What are bile salts?

Answer 15

Amphipathic molecules produced by the liver that emulsify fat.

Question 16

Function of bile salts in digestion?

Answer 16

Emulsify large fat globules into small droplets.

Question 17

What is a micelle?

Answer 17

A tiny lipid transport particle formed by bile salts surrounding fat.

Question 18

Why are micelles necessary?

Answer 18

Allow fat to cross the watery intestinal environment.

Question 19

Which receptor transports cholesterol into intestinal cells?

Answer 19

NPC1L1 receptor.

Question 20

Which drug blocks NPC1L1?

Answer 20

Ezetimibe.

Question 21

What enzyme converts cholesterol back into ester form inside enterocytes?

Answer 21

ACAT (Acyl‑CoA cholesterol acyltransferase).

Question 22

Why is cholesterol re‑esterified?

Answer 22

Safer storage and transport form.

Question 23

What are chylomicrons?

Answer 23

Large lipoproteins carrying dietary triglycerides and cholesterol.

Question 24

What components make a chylomicron?

Answer 24

Triglycerides, cholesteryl esters, phospholipids, and apolipoproteins.

Question 25

Where do chylomicrons go first after absorption?

Answer 25

Intestinal lymphatics (lacteals) then bloodstream.

Question 26

Structure of a triglyceride?

Answer 26

One glycerol backbone attached to three fatty acids.

Question 27

Functions of triglycerides?

Answer 27

Energy storage, insulation, and organ protection.

Question 28

After absorption, what happens to fatty acids?

Answer 28

Reassembled into triglycerides inside enterocytes.

Question 29

Why are lipoproteins required?

Answer 29

Lipids cannot dissolve in plasma.

Question 30

What are lipoproteins?

Answer 30

Particles that transport lipids through the bloodstream.

Question 31

Function of chylomicrons?

Answer 31

Carry dietary fat from intestine to tissues.

Question 32

Function of VLDL?

Answer 32

Liver exports triglycerides to tissues.

Question 33

Function of LDL?

Answer 33

Delivers cholesterol to peripheral tissues.

Question 34

Function of HDL?

Answer 34

Returns cholesterol to the liver (reverse cholesterol transport).

Question 35

Main apolipoprotein of LDL?

Answer 35

ApoB‑100.

Question 36

What receptor allows LDL entry into cells?

Answer 36

LDL receptor.

Question 37

Why is LDL dangerous?

Answer 37

Excess LDL becomes oxidised and forms foam cells and plaques.

Question 38

Main apolipoprotein of HDL?

Answer 38

ApoA‑1.

Question 39

Why is HDL protective?

Answer 39

Removes cholesterol from tissues and plaques to the liver.

Question 40

What enzyme acts on circulating chylomicrons?

Answer 40

Lipoprotein lipase (LPL).

Question 41

Function of LPL?

Answer 41

Breaks triglycerides into fatty acids for uptake by tissues.

Question 42

What happens to chylomicrons after LPL action?

Answer 42

Become remnants taken up by the liver.

Question 43

Which drugs increase LPL activity?

Answer 43

Fibrates.

Question 44

How does high cholesterol cause heart disease?

Answer 44

LDL oxidation → macrophage uptake → foam cells → plaque.

Question 45

Key concept linking this lecture to IHD?

Answer 45

Hyperlipidaemia initiates atherosclerosis.

Question 46

Effects of high triglycerides?

Answer 46

Low HDL, insulin resistance, obesity, pro‑thrombotic state.

Question 47

Which clotting factors increase with high triglycerides?

Answer 47

Factor VII, Factor X, and PAI‑1.

Question 48

What are apolipoproteins?

Answer 48

Proteins attached to lipoproteins regulating transport and receptor binding.

Question 49

ApoB‑100 indicates?

Answer 49

Atherogenic LDL particles.

Question 50

ApoA‑1 and ApoA-2 indicates?

Answer 50

Protective HDL. (protects from cardiovascular disease)

Question 51

ApoE4 association?

Answer 51

Increased risk of coronary artery disease and Alzheimer disease.

Question 52

Type I hyperlipidaemia?

Answer 52

Increased chylomicrons.

Question 53

Type IIa hyperlipidaemia?

Answer 53

Increased LDL (familial hypercholesterolaemia).

Question 54

Type IIb hyperlipidaemia?

Answer 54

Increased LDL and VLDL.

Question 55

Type III hyperlipidaemia?

Answer 55

Increased IDL.

Question 56

Type IV hyperlipidaemia?

Answer 56

Increased VLDL (high triglycerides).

Question 57

Type V hyperlipidaemia?

Answer 57

Increased chylomicrons and VLDL.

Question 58

Cause of familial hypercholesterolaemia?

Answer 58

Defective LDL receptors.

Question 59

Why does familial hypercholesterolaemia cause early MI?

Answer 59

Very high LDL accelerates plaque formation.

Question 60

How do statins work?

Answer 60

HMG co-A reductase inbibitor. Inhibit hepatic cholesterol synthesis and increase LDL receptor expression.

Question 61

How does ezetimibe work?

Answer 61

Blocks intestinal cholesterol absorption via NPC1L1.

Question 62

How do fibrates work?

Answer 62

Increase lipoprotein lipase activity lowering triglycerides.

Question 63

How do bile acid resins work?

Answer 63

Bind bile acids so the liver uses cholesterol to make more bile.

Question 64

Describe the full pathway from dietary fat to myocardial infarction.

Answer 64

Dietary fat → chylomicrons → VLDL → LDL → arterial deposition → oxidation → plaque → rupture → clot → myocardial infarction.

Question 65

Outline the process of intestinal cholesterol absorption.

Answer 65

Dietary cholesterol esters are hydrolysed by cholesterol esterase → bile salts form micelles → micelles deliver cholesterol to enterocyte → uptake via NPC1L1 receptor → ACAT re‑esterifies to cholesteryl esters → packaged with triglycerides and apolipoproteins into chylomicrons → enter lacteals (lymph) → bloodstream.

Question 66

What is the function of APOE?

Answer 66

APOE binds multiple lipoproteins (including VLDL and LDL) and mediates their uptake by the liver.

Question 67

What condition is APOE4 associated with?

Answer 67

Increased risk of both coronary artery disease and dementia (Alzheimer disease).

Question 68

What are the effects of the APOE2 genotype?

Answer 68

Increased risk of coronary artery disease but protective against dementia.