Atherosclerosis

Question 1

What is an arteriosclerosis?

Answer 1

General name for atherosclerosis where the arterial wall thickens and loses its elasticity, atherosclerosis is just the most common form

Question 2

What conditions would lead to arteriosclerosis?

Answer 2

coronary artery disease
cerebrovascular disease
peripheral artery disease

Question 3

What are the 3 stages of development?

Answer 3

The 3 I’s - insult, injury, inflammation
insult - endothelial damage where the permeability of it changes to macromolecules
injury - uptake of LDL particles, adhesion and infiltration macrophages
inflammation - SM migration from media to intima, collagen synthesis and plaque hardens forming a fibrous cap and foam cells die

Question 4

What are the 4 functions of the endothelium?

Answer 4

Vasomotor tone - vasodilators/vasoconstrictors
Thrombosis - anti/pro coagulants, platelet inhibitors/activators
Inflammatory factors - leukocytes
Cell adhesion molecules - receptors

Question 5

how can endothelial damage occur?

Answer 5

shear stress
toxic damage
high lipid levels
viral/bacterial infection

Question 6

What are the different types of lipoproteins?

Answer 6

Chylomicrons
VLDL
IDL
LDL
HDL

Question 7

What do chylomicrons contain and what apoproteins do they carry?

Answer 7

TG

B48 (A,C,E)

Question 8

What do VLDL’s contain and what apoproteins do they carry?

Answer 8

TG

B100 (A,C,E)

Question 9

What do IDL’s contain and what apoproteins do they carry?

Answer 9

TG & cholesterol

B100, E

Question 10

What do LDL contain and what apoproteins do they carry?

Answer 10

cholesterol

B100, E

Question 11

What do HDL contain and what apoproteins do they carry?

Answer 11

Protein

AI, AII

Question 12

How do macrophages infiltrate?

Answer 12

Monocytes bind to the endothelium and cross it to then transform into macrophages. They then accumulate large liquid droplets to become foam cells.

Question 13

How do LDL’s get uptakes?

Answer 13

LDL-receptor mediated endocytosis

via scavenger receptors as modified LDL is not recognised by LDL receptor

Question 14

How does smooth muscle proliferate?

Answer 14

endothelial cells and macrophages release growth factor PDGF
internal elastic lamina breaks down
PDGF is a chemoattractant for SM

Question 15

What are the types of smooth muscle?

Answer 15

Resting contractile

Proliferating which secretes ECM

Question 16

Where is the most common site for atheroma formation?

Answer 16

Carotid artery

Question 17

How can angina be formed from atheroscleroma?

Answer 17

An increase plaque volume means stenosis can occur in the lumen leading to angina

Question 18

What is angina?

Answer 18

Chest pain due to reduced blood flow to the muscles

Question 19

What can an unstable plaque result in?

Answer 19

Plaque can rupture leading to haemorrhages, release of tissue factor, platelet aggregation as collagen becomes exposed

reduces lumen diameter
thrombus formation
MI as may occlude lumen completely

Question 20

What are some unmodifiable RF for an atheromatous plaque?

Answer 20

age
sex
family history

Question 21

What are some modifiable RF for an atheromatous plaque?

Answer 21

smoking
hypertension
diabetes mellitus
physical activity
dyslipidaemia

Question 22

What is dyslipidaemia?

Answer 22

unhealthy levels of one or more kinds of lipid (fat) in your blood

Question 23

What should total cholesterol levels be for adults?

Answer 23

Under 200mg/dl

Question 24

What should LDL, HDL and TG levels be for adutlts?

Answer 24

LDL - under 130ml/dl
HDL - over 40 mg/dl
TG - 10-190 mg/dl

Question 25

How can cholesterol be reduced?

Answer 25

exercise, diet and drugs

Question 26

What are the treatments for high cholesterol?

Answer 26

Modify the risk factors | Statins to reduce plasma lipid levels

Question 27

How do statins work?

Answer 27

Inhibit HMG coA reductase to reduce intracellular cholesterol synthesis increase in lDL receptors reduce plasma cholesterol

Question 28

What are some complications of atherosclerosis?

Answer 28

Coronary artery disease leading to MI and angina peripheral vascular disease specifically peripheral arterial occlusive disease leading to ulcers, peripheral neuropathy and gangrene stroke aneurysm renal artery stenosis

Question 29

What is PTCA?

Answer 29

Percutaneous transluminal coronary angioplasty | minimally invasive procedure to open up blocked arteries allowing blood circulation

Question 30

How is PTCA done?

Answer 30

Balloon catheter is threaded into an obstructed area in the artery Balloon is inflated to stretch arterial wall and squash atherosclerotic plaque Lumen widened, balloon is deflated and catheter is withdrawn

Question 31

What is the purpose of a stent in an artery?q

Answer 31

Maintains the patency of a vessel

Question 32

What is the relationship between density of lipoproteins and their lipid: protein content?

Answer 32

Lower density of a lipoprotein means more lipid to protein.

Question 33

How can LDL's be modified?

Answer 33

Entrapped into subendothelial space Oxidised Glycation

Question 34

How are LDL's oxidised?

Answer 34

By free radicals | Deoxidised by antioxidants

Question 35

How are LDL's glycated?

Answer 35

By high glucose levels, seen in diabetes mellitus | Glycated LDL's are more likely to be oxidised

Question 36

How is LDL uptake controlled?

Answer 36

Negative feedback LDL receptors recognise apolipoproteins B100 and so uptake means they accumulate on the inside. This leads to a reduction in LDL surface receptors and therefore uptake.