11. Clinical I - Coronary and Peripheral Circulation (atherosclerosis) Flashcards
ATHEROSCLEROTIC PLAQUES form in which WALL LAYER of LARGE and MEDIUM SIZED ARTERIES
TUNICA INTIMA
how are SYMPTOMS of ATHEROSCLEROTIC PLAQUES
usually ASYMPTOMIC,
BENIGN lesions
Life-Threatening ISCHAEMIC (tissue dies due to lack of blood supply) DAMAGE to vital organs may only occur when what forms
when an OCCLUSIVE (blocking) THROMBUS (clot) forms ON a SPONTANEOUSLY DISRUPTIVE PLAQUE (ATHEROTHROMBOSIS)
what are the possible SITES (arteries) of ATHEROSCLEROSIS
- CORONARY ARTERIES to HEART
(myocardial ischaemia, unstable angina, myocardial infarction) - PERIPHERAL ARTERIES ie to Legs
(limb claudication) - CEREBRAL ARTERIES to BRAIN
Stroke (embolic or thrombotic) - RENAL ARTERIES to KIDNEYS
(atheroembolic renal disease, renal artery stenosis)
what different events can happen as a result of ATHEROSCLEROSIS
- NARROWING of vessel by FIBROUS PLAQUE
- Plaque ULCERATION or RUPTURE
- Intraplaque HEMORRHAGE
- Peripheral EMBOLI (clot)
- WEAKENING of vessel WALL (can lead to ANEURYSM - balooning which may rupture)
FORMATION of ATHEROSCLEROSIS starts with the FORMATION of what in young children (earliest significant lesions)
FATTY STREAKS
what do FATTY STREAKS consist of
LIPID-CONTAINING FOAM CELLS in the arterial just BENEATH the ENDOTHELOUM
over time they can evolve into atherosclerotic plaques or remain stable or even regress
how are FOAM CELLS FORMED in the process of the formation of an ATHEROSCLEROSIS
- INJURY to the ENDOTHELIUM of vessel triggers MONOCYTE ADHESION, Loosening of endothelial cell junctions and MIGRATION of MONOCYTES
- monocytes DIFFERENTIATE into MACROPHAGES
- MORE PERMEABLE ENDOTHELIUM also permits LOW-DENSITY LIPOPROTEINS (LDL) to ENTER the INTIMA of the artery
- MACROPHAGES ENGULF the LDL by PHAGOCYTOSIS
- after macrophages become LADEN with LIPID they are referred to as FOAM CELLS
when ENDOTHELIUM of a VESSEL is INJURED what is drawn to the site
MONOCYTES
which differentiate into MACROPHAGES
INJURED, MORE PERMEABLE ENDOTHELIUM of a vessel permits the ENTRY of what into the INTIMA that causes formation of FOAM CELLS (FATTY STREAKS) & ATHEROSCLEROSIS
LOW-DENSITY LIPOPROTEINS (LDL)
LOW DENSITY LIPOPROTEINS are PHAGOCYTOSED by … to FORM FOAM CELLS
MACROPHAGES
in the production of FOAM CELLS and ATHEROSCLEROSIS, what are also present in the INTIMA that are SECRETING CYTOKINES
T LYMPHOCYTES
T LYMPHOCYTES in INTIMA SECRETE CYTOKINES which cause what migration
SMOOTH MUSCLE CELLS in the TUNICA MEDIA MIGRATE INTO the INTIMA
- begin to PROLIFERATE under the influence of GROWTH FACTORS
progressive ACCUMULATION of LIPID / FOAM CELLS and SMOOTH MUSCLE CELLS in the INTIMA of artery walls / GROWING LESION begins to RAISE the ENDOTHELIUM and ENCROACH (intrude) on the LUMEN of the artery.
this lesion is known as a…
ATHEROSCLEROTIC PLAQUE
ATHEROSCLEROTIC PLAQUES evolve in 2 possible ways (2 pathways)
- how are SLOWLY GROWING PLAQUES
expand gradually due to accumulation of lipid in foam cells and migration and proliferation of smooth muscle cells
- STABILISE
*NOT PRONE TO RUPTURE
- the FIBRIN-CAP (thick) on top of the lesion MATURES