Cardio TBL Flashcards
Areteriosclerosis =
Hardening of Arteries
• Atherosclerosis: large and medium arteries;
INTIMAL CHANGES
—Lipid deposition, accumulation of macrophages + myointimal cells —>
plaque formation
• Arteriolosclerosis: Hypertension induced
hyperplasia/trophy of smooth muscle cells (Media)
• Endarteritis Obleterans:
Response to inflammation (syphilis); INTIMA
Arteritis:
• Arteritis: fibrinoid necrosis of arterial wall
Monkeberg’s:
Calcification of MEDIA
Areteriosclerosis Emphasis on Progression
• Intimal changes are persistent for decade(s), but then sclerosis can progress. Evidence shows lesions in same gross location, but different depth (in vessel wall) as individuals age.
Areteriosclerosis Presentation
• Presentation: 50 years of age
Arterial Structure Review Three Parts:
Intima:
Media:
Adventitia:
Arterial Intima:
Endothelium –> internal elastic lamella; contains myointimal cells in the sub-endothelial space
Arterial Media:
smooth muscle cells + Collagen I/III
Arterial Adventitia:
type I collagen + fibroblasts Vasa Vasorum not found in abdominal aorta –> more susceptible to athero.
CHRONIC ENDOTHELIAL DYSFUNCTION:
- Platelet Microthrombi
* Fatty Streaks
Platelet Microthrombi -
Proposed theory because aggregates of plat are found incommon sites of athero
Fatty Streaks -
Subendothelial lipid (cholesterol/esters) + foamy cells
- –No hemodynamic change
- –Reversible (Lactating babies +, 4-5 y/o)
Bottom Line: Endothelial injury
↑permeability for lipids + ↑adhesions
Endothelial Injury occurs from:
• Hyperlipidemia/hypercholesterolemia • HTN • Smoking • Diabetes/Metabolic Syndrome • Toxins/Viruses • Homocysteine Fatty streaks are reversible with lifestyle change. if not --> Fibrous (Fatty) Plaque
Areteriosclerosis Pathophysiology:
• Because Atherosclerosis = chronic endothelial dysfunction; any disease that causes endothelial injury can lead to it.
Three Consequence of endothelial injury:
- ↑Endothelial adhesion to leukocytes and platelets
- Passage of lipids (LDL) into subendothelial space (Fatty streak)
- DAMAGE –> endogenous activation macrophages–> ↑cytokines + ↑Macrophage presentation to T-Cells –> ↑T-Cell Inflammation
- ↑Endothelial adhesion to leukocytes and platelets leads to?
Adhesion Accumulation of macrophages, myointimal cells and monocytes (future foamy cells) in subendothleial space
- –Platelets on Fatty Streak –> ↑Cytokines –> ↑T Cell Activation
- **Cytokines–> Smooth muscle proliferation / ECM deposition (smooth muscle from tunica media –> tunica intima)
- Passage of lipids (LDL) into subendothelial space (Fatty streak) leads to?
- –LDL must be oxidized –> release inflammatory lipids
- –Can be modified by homocysteine (MI in Homocysteinuria)
- –Additional ↑Endothelial adhesion particles
- DAMAGE –> endogenous activation macrophages–> ↑cytokines +
↑Macrophage presentation to T-Cells –> ↑T-Cell Inflammation leads to?
—Inflammation –> ↑IL-6 –> ↑Acute Phase Proteins (SAA, CRP)
***CRP is best indicator of disrupted plaques; thus better than LDL for
predicting cardiovascular events
↑Endothelial adhesions leads to?
Macrophages and monocytes migrating: Lumen (L) to subendothelial space.
Once in subendothelial space,monocyte and macrophage ingests lipid –> Foamy Cell
Endothelial injury morphology?
• Fatty streaks: yellow streaks on
endothelium
• streaks occur at points of bifurcation
—Turbulent flow, likely place for injury