Lecture 20

Question 1

What is atherosclerosis?

Answer 1

Disease affecting the innermost layer of large and medium sized arteries

Question 2

How does atherosclerosis appear?

Answer 2

Focal thickenings known as plaques which are deposits of fibrous tissue and lipids

Question 3

What is arteriosclerosis?

Answer 3

A general term for hardening of the arteries

Question 4

What are the three major layers of artery walls?

Answer 4

Tunica intima, Tunica media, tunica adventitia these layers contain cells which continually communicate to regulate the fat ane function of other cells

Question 5

What makes up the tunica intima?

Answer 5

Endothelial cells on a basement membrane along with myointimal cells
Ocassionally in older people there will be multiple layes of endothelial cells, this is normal and does not always indicate a pathology

Question 6

What makes up the tunica media?

Answer 6

Elastic laminae and vascular smooth muscle cells which secrete cytokines and growthfactors as well as regulating vessel diameter

Question 7

What makes up the tunica adventitia?

Answer 7

Connective tissue

Question 8

What are the types of artery when they are classified by structure?

Answer 8

Large arteries have large elastic laminaes and are called elastic arteries
Most medium sized arteries are called muscular arteries as they are composed primarily of smooth muscle

Question 9

What are the four key risk factors for atheroscleorsis?

Answer 9

Hyperlipdaemia (High concentration of lipid in the blood)
Cigarette smoking
Hypertension
Diabete Mellitus

Question 10

What are the 10 positive non-key risk factors for atherosclerosis?

Answer 10

Advancing age
Family history
Male gender
high saturated fat diet
stressful and sedentary lifestyles
obesity
excess alcohol consumption
low birth weight
low socioeconomic status
infections

Question 11

What are the negative risk factors for atheroscleorsis

Answer 11

High levels of circulating HDLS
moderate alcohol consumption
cardiovascular fitness

Question 12

What are lipoproteins?

Answer 12

A lipid core surrounded by a apolipoprotein coat increased LDL will increase the risk of atherosclerosis while increased HDL will decrease the risk of athersclerosis as it removes lipid from the bllod

Question 13

What is atherogensis?

Answer 13

The pathogenesis of atherosclerosis

Question 14

What is the pathogenesis of athersclerosis?

Answer 14

There is an endothelial cell injury this then results in an inflammation response which involves leukocyte migration these leukocytes then activate smooth muscle resulting in the oversecretion of extracellular matrix, Lipoproteins are then ingested and oxidised resutling in the formation of plaques

Question 15

What are three possible causes of endothelial cell injury and waht are the consequences of this injury?

Answer 15

The sheer force of blood can damage endothelial cells, particularly at branch points
Chemical insults
Cytokines
These injuries will result in altered permeability of the membrane (allowing lipid infiltration)
Adhesion of leukocytes
Activation of thrombosis

Question 16

What occurs in the leukocyte migration phase of atherogenesis?

Answer 16

Circulating monocytes enter the atherosclerotic lesion
These then ingest large amounts of oxidised lipoprotein to form foam cells
other immune cells perform important tasks in this process

Question 17

What occurs in the phase of smooth muscle activation and migration in atherogenesis?

Answer 17

Macrophages, platelets and endothelial cells produce growth factors activating smooth muscle
Activated smooth muscle will proliferate and move to the tunica intima which may damage the internal elastic lamina
They then lay down extracellular matrix which contributes to the fibrous cap (potentially later digested by matrix degrading protease)
Vascular smooth muscle will also ingest lipid and interact with other plaque cells

Question 18

What occurs in the lipoprotein phase of atherogenesis?

Answer 18

Lipoproteins are oxidised, attracting monocytes and stimulating the release of cytokines and growth fators, these cause dysfunction and apoptosis in smooth muscle, macrophages and endothelial cells

Question 19

What are the consequences of atherosclerosis?

Answer 19

Atheroma are typically silent but will often rupture or encounter a blood clot to cause sudden, severe symptoms such as myocardial infarction, peripheral vascular disease and cerebrovascular disease

Question 20

What do new technologies show about atherosclerosis?

Answer 20

Many genes have been implicated but no one ‘killer’ gene has been identified suggesting that atherosclerosis is a pattern polygenomic inheritance and requires interaction from environmental factors