Fung > Vascular Path Flashcards
what is ECM made of?
elastin
collagen
glycosaminoglycans
what are the 3 components of the vasculature?
endothelial cells
smooth muscle cells
ECM
what are the 5 fxns of the endothelial cells?
maintain non-thrombogenic blood-tissue interface modulate vascular resistance metabolize hormones regulate inflammation regulate cell growth
which component of the vasculature proliferates when stimulated?
smooth muscle cells
what do smooth muscle cells synthesize?
collagen
elastin
proteoglycans
what do smooth muscle cells elaborate?
growth factors
cytokines
what are the 3 layers of the vasculature?
intima
media
adventitia
what are the 2 specialized layers in muscular arteries?
internal elastic lamina
external elastic lamina
T/F: arteries have valves
false
veins do
where do berry aneurysms occur?
cerebral vessels
T/F: the majority of berry aneurysms occur sporadically
TRUE
what are 4 possible genetic causes of berry aneurysms?
AD polycystic kidney disease
Ehlers-Danlos syndrome
NF1
Marfan
what are 2 risk factors for developing berry aneurysms?
cigarette smoking & HTN
are berry aneurysms present at birth?
no
they develop over time
(they’re still inexplicably called congenital though)
what are atriovenous fistulas?
small direct connections btwn arteries & veins that bypass capillaries
can inflammatory necrosis of adjacent vessels cause AV fistulas?
yes
can developmental defects cause AV fistulas?
yes
can penetrating injuries that pierce arteries & veins cause AV fistulas?
yes
can rupture of an arterial aneurysm into an adjacent vein cause an AV fistula?
yes
can AV fistulas be iatrogenic?
yes
what is fibromuscular dysplasia?
focal irregular thickening of the walls of medium & large muscular arteries
what does fibromuscular dysplasia result in?
luminal stenosis
at what age does fibromuscular dysplasia occur?
any
in what group is fibromuscular dysplasia most common?
young women
what is an aneurysm?
localized abnormal dilation of a blood vessel or the heart
T/F: aneurysms are always acquired
false
they can also be congenital
what are the 2 types of aneurysms?
true
false
what are the 2 forms of true aneurysms?
saccular
fusiform
what is a true aneurysm?
involves an intact attenuated arterial wall or thinned ventricular wall
what are 4 examples of true aneurysms?
atherosclerotic
syphilitic
congenital
ventricular following transmural infarction
what is another name for a false aneurysm?
pseudo-aneurysm
what is a false aneurysm?
a defect in the vascular wall leading to an extravascular hematoma that freely communicates w/ the intravascular space
what is an example of a false aneurysm?
ventricular rupture w/ pericardial adhesion
what is a saccular true aneurysm?
spherical outpouchings involving only a portion of the vessel
how big are saccular true aneurysms?
5-20 cm diameter
what is a fusiform true aneurysm?
diffuse circumferential dilation of a long vascular segment
how big are fusiform true aneurysms?
up to 20 cm diameter
where can you find fusiform true aneurysms?
extensive portions of the aortic arch
abdominal aorta
iliac arteries
what can cause an aneurysm to form (generally)?
any process that causes weakening of the vessel wall
what are the 2 main general causes of aneurysms?
sporadic
OR
connective tissue disease
what is Marfan syndrome?
a defect of fibrillin
what is Ehlers-Danlos?
a defect in the synthesis or structure of fibrillar collagen
what is Vitamin C deficiency?
altered collagen cross-linking
what is Loeys-Dietz syndrome?
a defect in elastin, collagen I, & collagen III
how can inflammation cause an aneurysm?
alters the balance of synthesis & destruction of collagen
increased matrix metalloproteases (MMP) degrade the ECM
what causes a thickening of the intima and cystic medial degeneration?
loss of smooth muscle cells
OR
proliferation of non-collagenous/non-elastic ECM
what is the consequence of a thickened intima?
decreased diffusion of oxygen and nutrients to the media
what are the 2 most important predisposing factors for aneurysms?
HTN & atherosclerosis
what does atherosclerosis cause particularly?
AAA
abdominal aortic aneurysm
what does HTN cause particularly?
ascending aortic aneurysm
can infection cause an aneurysm?
yes d/t embolization, direct extension, or organism circulation
can aneurysms be congenital?
yes (developmental berry aneurysms)
what is the most common location of atherosclerotic aneurysms?
abdominal aorta
how do AAAs form?
cystic medial degeneration results in thinning & weakness
what is a major influence for developing AAA?
increased MMP (matrix metalloproteases)
T/F: AAAs are always saccular
false
they can be saccular or fusiform
what is an inflammatory type AAA?
dense periaortic fibrosis containing abundant lymphocytes, plasma cells, & macrophages
what is a mycotic type AAA?
d/t circulating microorganisms that destroys the media
what are the 4 clinical consequences of a AAA?
rupture w/ potential fatal hemorrhage
obstruction of branch vessel
embolism from atheroma or mural thrombus
impingement on adjacent structures
what is a thoracic aneurysm most commonly assoc w?
HTN
what are the sx of a thoracic aneurysm?
bone pain
cough (pressure on recurrent laryngeal nerve)
aortic valve dilation w/ insufficiency
what can a TAA encroach on?
mediastinal structures
lungs & airways
esophagus
what is a dissection?
blood splays apart the laminar planes of the media to form a blood filled channel w/i the vessel wall
T/F: dissection is always assoc w/ vessel dilation
FALSE (may or may not be assoc w/ it)
who gets dissections?
men 40-60 yo w/ HTN
younger pts w/ systemic & localized abnormalities of the aorta
why don’t you usually see dissection w/ atherosclerosis?
bc of medial fibrosis
what is the major risk factor for dissection?
HTN
what is the pathophysiology of dissection?
medial hypertrophy of the vasa vasorum w/ degenerative changes of the media
i.e. injury d/t diminished flow
what 3 tissue disorders can lead to dissection?
Marfan
Ehlers-danlos
Vitamin C deficiency
what is the most frequent histologically detectable lesion w/ dissection?
cystic medial degeneration
what is a Type A dissection?
a proximal lesion involving either the ascending aorta only or in conjunction w/ the descending aorta
what DeBakey types are assoc w/ Type A dissection?
I & II
what is a Type B dissection?
distal lesion beginning distal to the subclavian artery & NOT involving the ascending aorta
what DeBakey types are assoc w/ Type B dissection?
type III
what is DeBakey type I?
involves ascending AND descending aorta
type A
what is DeBakey type II?
involves ascending aorta only
type A
what is DeBakey type III?
involves the descending aorta only (distal to subclavian)
type B
what is vasculitis?
general term for vessel wall inflammation
what do the clinical features of vasculitis depend on?
which vascular bed is affected
T/F: vasculitis affects only small vessels
false
affects any vessels of any organ or any size
what are the 2 most common pathogenic mechanisms of vasculitis?
immune-mediated inflammation
direct invasion of vascular walls by infectious pathogens
T/F: infectious pathogens can initiate both infectious AND non-infectious vasculitis
true
idk why
what vessels does large vessel vasculitis affect?
aorta
large branches to extremities/head/neck
what are 2 types of large vessel vasculitis?
Giant cell (temporal) arteritis Takayasu arteritis
what vessels does medium vessel vasculitis affect?
main visceral arteries & their branches
what are 2 types of medium vessel vasculitis?
Polyarteritis nodosa
Kawasaki disease
what vessels does small vessel vasculitis affect?
arterioles
venules
capillaries
small arteries
what vessels does variable vessel vasculitis affect?
no predominant type
what are 2 types of variable vessel vasculitis?
Behcet’s disease
Cogan’s syndrome
what is the mechanism for large vessel vasculitis?
granulomatous disease
what is the mechanism for medium vessel vasculitis?
immune-complex mediated
OR
anti-endothelial cell ab
what are the mechanisms for small vessel vasculitis?
immune complex mediated
OR
paucity of immune complexes (often w/ ANCA)
what are the 4 types of immune-complex mediated small vessel vasculitis?
SLE
IgA
Cryoglobin
OTHER
what are the 3 types of “paucity of immune complexes” small vessel vasculitis?
vasculitis w/o asthma or granulomas
granulomas, no asthma
eosinophils, asthma, & granulomas