Flashcards in Blood vessels and arteriosclerosis Deck (85)
What are some medium-sized or muscular arteries?
coronary arteries and renal arteries
What are the large or elastic arteries?
aorta and major branches, and pulmonary artery
What is the structure of small arteries and arterioles?
media essentially all smooth muscle cells
arterioles thin internal elastic membrane; terminal artiorles no elastic
What is the purpose of venules?
points where leukocytes emigrate in inflmmation
What is the response of endothelial cells in response to injury?
stimulation: rapid, reversible responses independent of new protein synthesis
activation: elaboration of gene products with biologic activity requires hours/day to develop
Where do vascular smooth muscle cells migrate to?
intima and proliferation occurs in normal vascular repair and pathologic processes
What are ht pro-growth factors associated with vascular smooth muscle cells?
pro-growth factors: PDGF, endothelin, thrombin, FGF, IFN-gamma, IL-1
What are the clinical significance of vascular disease?
responsible for more morbidity adn mortality;
two basic pathologies
-narrowing or obstruction-atherosclerosis and associated thrombosis
weakening of the vessel wall
-dilation adn rupture
How does intimal thickening occur?
stereotyped resposne to vascular injury of any kind
-recruitment of smooth muscle cells or smooth muscle precursor cells to the intima
2. smooth muscle cell mitosis
3. elaboration of extracellular matrix
intimal smooth muscle cells cannot contract
healing response which may narrow or occlude the vessel
What is the arteriosclerosis?
hardening of artiers;
small arteries and arterioles
-monckeberg medial calcific sclerosis
What is atherosclerosis
elastic arteries and large/medium muscular arteries
-most common: contributes to 50% ofall death
What is monckeberg arteriosclerosis?
calcific deposits in media of medium sized muscular arteries
no obstruction to the blood flow
usually not clinically significant
unrelated to atherosclerosis
What is atherosclerosis?
most prevalent and signifcant disease pattern
-- progressive disease of elastic arteries and large to medium-sized muscular arteries
two basic types of damage
aneurysm formation and stenosis
What is the clinical syndrome associated with atherosclerosis in elastic arteries?
=aorta--aneurysm with rupture
--carotid arteirs -occlusion causing stroke
--iliac arteries - occlusion causing gangrene
What is the clinical syndorme associated with atherosclerosis in medium// large sized muscular arteries?
coronary arteries- occlusion leads to MI
popiteal arteries -- cause gangrene
renal artery- narrowingocclusion causing secondary HTN
mesenteric arteries -- narrowing/occlusion causing bowel infarction
What is the morphology of fatty streak?
multiple yellow, flat dots to streaks, usually in aorta and later in cornoaries; may be precursor to atheromas
What is lipid incorporation?
LDL cholesterol is transported into the vessel wall
endothelial cells and monocytes/macrophages generate free radical that oxidize LDL resulitng in lipid peroxidation
oxLDL is taken up by macrophages via scavenger receptors; resulting in activationa dn release of proinflammatory cytokines
What is the fibro-fatty plaque?
raised yellow-white plaque in intima with soft yellow core and white fibrous cap
-- fibrous cap
-- necrotic center
What is the risk of advanced/vunerable plaques?
are at risk for:
ruptured ulceration, erosion and hemorrhage
-progressive luminal narrowing
What are the signs of a vunerable plaque?
small fibrous cap, more inflammationa dn larger lipid cores
What is thrombosis?
partial or complete occlusion of vessel lumen: thrombus may be incorporated into the lesion, further narrowing it; likely happens repeatedly
What are factors contributing to thrombosis?
shear stress, high levels of LDL, smoking, through elevation of fibrinogen
What is the anuerysm formation?
atrophy of media, destruction of elastic fibers
leads to thinned weakend wall prone to rupture
What is atherosclerosis pathogenesis-1?
chronic inflammatory response of arterial wall to endothelial injury
What is atherosclerosis pathogenesis-2?
chronic endothelial injury/dysfunction; incrased permeability, enhanced leukocyte adhesion
-specific cause unknown
-strongly suspected causes:
What is the atherosclerosis pathogenesis-3?
adhesion molecules attract leukocytes
monocytes adhesion, migration, and transformation to macrophages
-T lymphs: secretion of cytokines and fibrogenic mediators
What is the atherosclerosis pathogenesis-4?
infection: importance is unclear at present
-HSV, CMV, Chlamydia
smooth muscle cells: proliferation and migration into intima withproduction of matrix proteins
How does cholesterol cytotoxicity occur?
formation of cholesterol crystals
triggering of apoptotic pathways
formation of toxic oxysterols
disruption of membrane domains that are crucial for function of enzymes and signaling molecules
contributionto mechanisms that promote atherosclerosis