Vascular Biology of Atherosclerosis Flashcards
Tunica intima
inner layer of vessel wall
The tunica intima is composed of…
- endothelial layer
- internal elastic lamina
- subendothelium
endothelial layer
monolayer of simple squamous epithelium cells that line the lumen
internal elastic lamina
subendothelial basement membrane layer made up of loose connective tissue support endothelium
subendothelium
space between endothelium and internal elastic lamina
tunica media
middle layer of blood vessel wall
The tunica media is composed of…
- smooth muscle cell layer
- extracellular matrix (ECM)
Smooth muscle cell layer
normal smooth muscle cells responsible for smooth muscle vasomotor tone
extracellular matrix (ECM)
made up of collagen, elastin, and proteoglycans
collagen
load bearing protein
elastin
elastic protein functions to cushion vessel during changes in pressure
proteoglycans
glycosylated proteins main part of ECM (for structural support)
What are the 2 normal functions of VSMC?
- contractile function
- synthetic function
Contractile functions alter the ?? of the lumen through ?? and ??.
- diameter
- vasodilation
- vasoconstriction
Nitric oxide and prostacyclin are examples of?
vasodilators
Angiotensin II and endothelin-1 are examples of?
vasoconstrictors
Synthetic functions produce ??, ??, and ??; which make up the ?? in the ECM.
- collagen
- elastin
- proteoglycans
- tunica media
Tunica externa
outermost layer of blood vessel wall; contains nerve fibers and lymph vessels
The tunica externa is made up of…
- collagen fiber network
- external elastic lamina
- vasa vasorum
collagen fiber network
reinforces blood vessel and anchors to surrounding tissues
external elastic lamina
connective tissue lying immediately outside the smooth muscle of the tunica media
vasa vasorum
tiny blood vessels that supply the external layer of blood vessel wall
What are the 5 normal functions of the endothelial layer?
- barrier function
- anti-thrombotic function
- vascular tone function
- migratory/proliferation of VSMC
- anti-inflammatory immune function
Endothelial layer: barrier function
restrict passage of large molecules into subendothelial space
Endothelial layer: anti-thrombotic function
- secretes anti-clotting factors
- secretes platelet inhibitors/anti-aggregation factors
example of anti clotting factors
heparin sulfate
example of platelet inhibitors/anti-aggregation factors
nitric oxide
Endothelial layer: vascular tone function
- increased secretion of vasodilators
- decreased secretion of vasoconstrictors
example of vasodilator
nitric oxide
examples of vasoconstrictor
endothelin-1
Endothelial layer: migratory/proliferation of VSMC function
inhibits migration of VSMCs from media to intima
Endothelial layer: anti-inflammatory immune function
- suppress leukocyte (WBC) adhesion to endothelial wall
- suppress expression of chemokines (attract WBCs) on endothelial wall
- suppress expression of adhesion molecules (adhere WBCs)) on endothelial wall
arteriosclerosis
generic term for thickening of the blood vessel (arterial) wall
“athero”
gruel or wax; corresponds to the lipid/necrotic core area at the base of the athersclerotic plaque
concentric lesion
thickening of tunica media of artery
“sclerosis”
hardening; referring to the fibrous cap of the plaque’s luminal edge
atherosclerosis
eccentric arteriosclerosis
What causes concentric lesions?
proliferation of VSMCs
Concentric lesion can be described visually as…
symmetric narrowing of the vessel (arterial) lumen
Disease of Aging
concentric lesion
Concentric lesions typically referred to as…
arteriosclerosis
eccentric lesion
tunica intima thinkening (subendothelial) of artery
Eccentric lesion can be visually described as…
asymmetric narrowing of vessel wall
What causes eccentric lesions?
accumulation of oxidized lipids, macrophages, VSMCs, platelets, tissue factor
Eccentric lesion develop from
- immature “??” into “??”
- ?? that protudes into lumen of artery
- fatty streak
- mature plaque
- lesion
Eccentric lesions are typically called…
atherosclerosis
Development of Eccentric lesions
fatty streaks
earliest form of eccentric lesion
Development of Eccentric lesions
Fatty streak are made up of subendothelial accumulation of ??.
foam cells
Development of Eccentric lesions
?? are macrophages that take up oxidized and modified lipids.
Foam cells
Development of Eccentric lesions
appearance of fatty streaks
yellow, minimally raised lesions
Development of Eccentric lesions
When do fatty streaks appear?
very young age; teens - vets
Development of Eccentric lesions
Fibrous plaques
advanced eccentric lesion