Question

****biology*****

Briefly explain the process of atherosclerosis starting from endothelial injury to plaque formation.

please make it not that complex for non biology major student thx! :)

Answer 1

Atherosclerosis is an thickening and hardening of large and medium sized muscular arteries,primarily due to involvement of tunica intinma.( It's a layer of blood vessel)

It is charaterised by fibrofatty plaques or atheromas.

Large and medium sized arteries are involved mainly,

Aorta,coronary and cerebral arterial sysytems are affected highly.

It is not caused by single factor,but it is a multifactoral process. It's exact pathogenesis is not clear. There are many hypothesis in function like insudationhypothesis, encrustation hypothesis etc..,

But widely accepted is Reaction to injury Hypothesis:-

It involves

1)endothelial injury

2)Intimal smooth muscle proliferation

3)Role of blood monocytes

4)Role of dyslipidaemia

5)Thrombosis

=}Trauma to endothelium of blood vessels causes damages to it exposing sub endothelial tissues to the blood.

=}endothelial injury causes release, adherence,aggression of platelets at exposed site of sub endothelial tissues.

There is infiltration of inflammatory cells.

-Proliferation of Intimal smooth muscle cells.

-cytokines such as IL-1 are released from macrophages leading to local synthesis of growth factors like platelet derived growth factors, transforming groth factor, etc..,

=}Blood monocytes forms foam cells by LDL(low density lipoprotein).

These foam cells enter damages tissues.

Death of foam cells by apoptosis relases these LDL into tissues causing formation fibrofatty plaques.

=}Small platelet aggregates at site causes proliferation of smooth muscle cells. This causes mild inflammatory response,which along with foam cells incorporates into plaques

These forms enlarge by attaching fibrin and cells from surrounding blood. This thrombus becomes part of plaques.

This is total process, in general steps

1)endothe endo dysfunction

2)plaque formation/fatty streak

3)Fibrous plaque is seen

4)plaque ruptures to cause thrombosis.

5) thrombus migrates to form atheromas in other arteries.