Cardio vascular Flashcards
What is Atherosclerosis?
chronic inflammatory disease of the arterial wall, deposition of lipid in the arterial wall is key to pathogenesis, it is the MAIN cause of CVD, can take decades to develop
Structure of arteries - outside in
Tunica adventitia
Tunica Media
Tunica intima
Lumen
Tunica intima
inner layer, single layer of endothelial cells in direct contact with blood
Tunica Media
middle layer, smooth muscle cells, arteries can change diameter, gives structural integrity
External elastic lamina
connective tissue on the outside of Tunica media, separates the media from the outer layer of the vessel
Tunica Adventitia
Outer layer of blood vessel, made of Fibroblasts and collagen, contains the vaso vasorum a way for large vessels to have their own blood supply as oxygen and nutrients cannot diffuse to the outer layer
What are lipoproteins?
Lipids that are packaged in proteins to enable their transit in the body
The lipid cargo of lipoproteins
Cholesterol, cholesterol esters, triglycerides, fatty acids and phospholipids
Lipoprotein synthesis
Chylomicrons made in intestine - Chylomicrons used for lipids, chylomicrons remnants are cleared by liver, VLDL is synthesized in the liver, VLDL is converted to IDL and LDL in blood liver and peripheral tissue
3 hypotheses for atherosclerotic plaque buildup
- Response to endothelial injury
- Response to Retention
- Response to oxidation
Injury hypothesis for atherosclerosis
Lesions form at artery branches, low ESS causes turbilent flow and damages the endothelial wall making the it more permeable to LDL and increases LDL transport into the wall
Response to oxidation hypothesis for atherosclerosis
LDL modified to be pathogenetic, oxLDL is formed in arterial wall, oxLDL acquires new functions and triggers inflammatory response, oxLDL is taken up by macrophages, lipid accumulates in the cytoplasm of the cell, foam cells form = lipid laden macrophages = formation of fatty streak which is the initial lesion of atherosclerosis
