Atherosclerosis & CAD Flashcards
What is the innermost layer of an artery?
Tunica Intima
What is the Tunica Intima made up of?
Endothelium, Subendothelium, Elastic membrane
What does the endothelium of the Tunica Intima do?
It is a thromboresistant layer between blood and subendothlial tissue that modulates tone, growth, hemostasis and inflammation
What is the middle layer of an artyer?
Tunica Media
What does the Tunica Media consist of?
Smooth muscle cells and and elastic membrane
What is the outer layer of an artery?
Tunic Externa/Adventitia
What is the Tunica Externa made up of?
Composed of extracellular matrix with fibroblasts, mast cells and nerve terminals
Describe how atherosclerosis progresses
1) Fatty streak forms
2) Fibrous plaque proliferates
3) Lesion develops
4) Fibrous cap develops
5) Vasa Vasorum is disrupted
6) Intraplaque hemorrhage
Describe the pathology for first step of Atherosclerosis progression (aka Fatty Streak formation)
Tunica Intima and extracellular matrix thickens due to foam cells accumulating
Foam cells accumulating causes the fatty streak to form
How do foam cells form?
Vascular injury causes monocyte to bind to endothelium
Monocytes cross through the endothelium and become activated macrophages
Macrophages eat the LDL which become FOAM CELLS
Describe the pathology for step 2 of atherosclerosis progression (aka Plaque Formation)
The fatty streaks (from foam cells), debris and lipid-filled-connective tissue develop into plaque
Describe the pathology of step 3 of atherosclerosis progression (aka Advanced Lesions Developing)
Necrotic lipid-rich core and calcified regions form as the plaque continues to build
This larger plaque is called an ‘atheroma’
Coronary arteries will respond to the atheroma by doing positive (increase vessel size) and negative (vessel shrinkage) remodeling
Describe step 4 of atherosclerosis progression (aka Fibrous Cap Formation)
As the Plaque and Atheromas continue to develop, a collagen-based layer of connective tissue will cover it as the body attempts to stabilize the condition
Describe step 5 of atherosclerosis progression (aka Vasa Vasorum is disrupted)
Vasa Vasorum is the term for the microvessels on the outer layer of arteries.
When the plaque expands, they will obtain their own microvessels
Describe step 6 of atherosclerosis progression (aka Intraplaque hemorrhage)
The microvessels that have infiltrated the plaque can become unstable and cause ischemic events such as rupturing and eventually causing thrombosis
When atherosclerosis develops, it can impede the availability of _____ which is needed by the vessels to dilate and constrict
Nitric Oxide