Atherosclerosis Flashcards
Atherosclerosis is one type (the most common type) of what condition?
Arteriosclerosis
What is the effect of the accumulation of atherosclerotic plaque to the vessel lumen size?
The lumen decreases due to the accumulation of plaque along the arterial wall
What are the two main immune cells involved in atherosclerosis?
Macrophages and T cells
Atherosclerosis directly involves the accumulation of _____ (HDL/LDL).
LDL - low density lipoprotein. This steamed the bad cholesterol because it directly involved in the progression of atherosclerosis.
Identitfy 3 CVS conditions associated with atherosclerotic plaque accumulation.
Myocardial infarction
Stroke
Peripheral vascular disease
What are the 3 histological layers of an artery?
The tunica intima, media and adventitia
Which of the 3 layers of the arterial wall is most deep (close to the lumen)?
The tunica intima
Which of the 3 layers of the arterial wall is most superficial (furthest from the lumen)?
The tunica adventitia
The tunica intima is primarily composed of which tissue?
A single layer of endothelial cells.
It has a basement membrane which is the anchoring point for the endothelial cells.
The tunica adventitia is primarily composed of tissue(s)?
Connective tissue
Vasa vasorum (blood supply to the artery wall)
Nervous fibers
The tunica media is primarily composed of tissue(s)?
Smooth muscle
Elastin (allows the vessels to stretch to accomodate for increased blood volume).
What are the two types of arteries?
Elastic and muscular
What is the characteristic feature of elastic arteries?
They contain a high amount of elastin in the tunica media layer of the artery.
What is the functional use of elastic arteries?
The are able to stretch a lot - facilitates expansion during systole and contraction during diastole.
Give 3 examples of elastic arteries.
The aorta, carotid artery and iliac arteries.
What is the characteristic feature of muscular arteries?
A layer of smooth muscle in the tunica media of these arteries.
What is the functional use of muscular arteries?
Allows for vasoconstriction and vasodilation to modify blood flow.
What is the smallest muscular artery?
The arterioles are the smallest muscular arteries - they also have the highest resistance to flow.
Describe the basic pathophysiology of atherosclerotic plaque development.
The LDL floating the blood stream is oxidised by free radicals.
The oxidised LDL is taken up by macrophages which are unable to degrade the lipids and eventually become foam cells.
Foam cells and lipids buildup in the tunica intima forming atherosclerotic plaque.
Why is atherosclerosis termed a “chronic inflammatory process”?
The oxidised LDL is damaging to the smooth muscle cells and endothelium -which draws macrophages to the area. The macrophages can also release cytokines which attract T cells.
How can smooth muscle cell proliferation drive atherosclerotic plaque development?
Smooth muscle cell proliferation is driven by PDGF (platelet derived growth factor). The smooth muscle secrete extracellular matrix which is a component of atherosclerotic plaque.
Outline the two main phases of atherosclerotic plaque development.
- Fatty streak - the fatty streak is comprised of macrophages and LDL
- atherosclerotic plaque - the tunica intima thickens due to the accumulation of lipids - which form patchily along the vessel wall.
List (in order) the five most common locations for atherosclerotic plaque development.
- abdominal aorta
- coronary arteries
- popliteal arteries
- internal carotid arteries
- circle of willis
A atherosclerotic plaque rupture can be fatal due to what reason?
The rupturing of the plaque can expose thrombogenic fibres (pro-clotting fibres) which can lead to the development of a clot which can occlude the blood vessel.
Outline the consequences of a haemorrhage into plaque.
The rupture of plaque can be contained within a lesion. which causes the lesion to expand rapidly - leading to vessel occlusion
Outline the consequences of an aneurysm
Lesions can damage the tunica intima of the arterial wall leading to aneurysm (or ballooning of the arterial wall).
What is an infarction?
An infarction is tissue death as a result of ischemia (or lack of oxygen).
What are the two types of ischemia?
White and red infarction
What is a white infarction?
Total or complete occlusion of the blood vessel preventing blood to the distal healthy tissue - the ischemic tissue becomes white.
Where are common places for white ischemia to occur?
Solid organs like the heart, kidneys, and spleen
What is a red infarction?
Partial occlusion of the blood vessel preventing all blood from supplying the distal healthy tissue - the ischemic tissue appears red.
