Pathogenesis of Atherosclerosis

welcome to another path on video the topic of this video is a thorough sclerosis atherosclerosis is a condition where lipid plaques form within the walls of arteries it is a specific type of arterial sclerosis which is the generalized condition of hardening of arterial walls whereas atherosclerosis is specific to the build-up of lipids that cause arterial walls to narrow and restrict blood flow atherosclerosis can be especially dangerous for the heart since it often affects coronary arteries which supply oxygen and nutrients to the heart in severe cases when blood flow through the coronary arteries is cut off a heart attack also known as a myocardial infarction can occur or heart cells or cardiac myocytes are deprived of oxygen may die normally most of the low-density lipoproteins or LDLs passed through the endothelial cells by trans cytosis from the blood and then enter body cells by receptor mediated endocytosis to be used in normal cell processes the progression of atherosclerosis begins when the endothelial cells of the arterial wall become damaged this can be caused by hypertension smoking hyperglycemia and hypercholesterolemia which is an increased number of LDLs in the blood endothelial cell damage increases the permeability of the arterial wall allowing LDLs to enter the Tunica intima white blood cells such as monocytes normally move freely through the blood vessels and do not attach to endothelial cells as a stream passed however when endothelial cells are exposed to irritating stimuli or damage they will express adhesion molecules that can capture nearby white blood cells these white blood cells undergo morphological changes that allow them to flatten and squeezed between endothelial cells this movement of white blood cells out of the bloodstream is called diet PD sis white blood cells are capable of producing free radicals and when these free radicals come in contact with LDLs oxidation occurs oxidized LDL particles are especially effective at attracting and activating white blood cells white blood cells that engulf the modified LDL particles which stimulates them to produce even more oxygen free radicals it becomes easy to imagine that an area of endothelial damage will lead to an accumulation of modified LDL particles and migrating wet white blood cells a positive feedback situation begins to arise when accumulating immune cells and modified LDLs bring in even more immune cells and modified LDLs macrophages in the Tunica intima start to engulf modified LDL particles ultimately this leads to the production of a cell called a foam cell a foam cell is saturated with LDL particles and the excessive amount of lipid in the cell gives the cytoplasm of foamy appearance foam cells ultimately die and release their contents which are then quickly engulfed by other nearby white blood cells please note that the animation shows smooth muscle cells also engulfing LDL cholesterol eventually the accumulating lipid from the processes just described and the fragments of dead cells produce an area with the lipid core that begins to form a plaque endothelial cells cover the plaque the plaque accumulates calcium salts and more dead cells over time and it will harden this plaque in the arterial wall is atherosclerosis if the endothelial cells over the plaque are compromised blood clots can form on the vessel wall remember that healthy endothelial cells normally Express inhibitors of clotting but now since they are damaged they no longer do this over time ruptured areas of plaque may create a situation where an area of plaque may jut out into the vessel lumen a clot that forms and attaches to the wall is called a thrombus if the clot breaks loose from the arterial wall and floats downstream to even smaller vessels it is called an embolus here is an animated summary now of the pathogenesis of atherosclerosis thanks for watching

Channel: PhysioPathoPharmaco

Views: 302,117

Rating: 4.9453502 out of 5

Keywords: atherosclerosis, pathogenesis, white blood cells, plaque, fatty deposits, hypertension, hyperlipidemia, hyperglycemia, smoking, diapedesis, LDL, foam cell, low density lipoprotein, oxidized LDL, free radical, free radicals, adhesin proteins, calcium salts, plaques, thrombus, embolus, emboli, thrombi

Id: N33JsBeziEY

Length: 6min 6sec (366 seconds)

Published: Fri Aug 11 2017