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2 Process Heart Disease_SW_REV

2 Process Heart Disease_SW_REV - KNES 260 Lecture 1...

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Unformatted text preview: KNES 260 Lecture 1 : Review/Questions Lecture 2 : The Process of Heart Disease Review: Heart Attack vs. Angina Review: Heart Attack vs. Angina 3 main differences between Angina and MI 1. The pain is more severe 2. The pain lasts longer than 5 min. 3. Resting and/or Nitroglycerin (drug to open the blood vessels) does not relieve the pain. With angina, the heart does not receive enough oxygen. If lifestyle is not changed, the condition will worsen When the coronary arteries are completely blocked, a heart attack occurs. Process of Heart Disease Process of Heart Disease Reading Articles #2­4 Process of Heart Disease ∙ Outline the 3 stages of the atherosclerotic process. ∙ Describe the anatomy and basic physiology of an arterial blood vessel. ∙ Explain the significance of endothelial cells, foam cells, and low­density lipoprotein cholesterol in the development of fatty streaks. ∙ Explain the factors that “injure” endothelial cells. ∙ Explain the significance of smooth muscle cells and endothelial cells in the Fibrous Plaque stage of atherosclerosis. ∙ Explain the two primary things that happen to the lesion in the Advanced Lesion Formation stage. ∙ Explain the three major outcome possibilities in the Advanced Lesion Formation stage. Process of Heart Disease Process of Heart Disease Called atherosclerosis Not a very simple process Actually a complex three­step process Cardiovascular Overview Cardiovascular Overview Overview of the Cardiovascular System and heart function Video (www.mayoclinic.com) Heart is a 4­Chamber pump Moves de­oxygenated blood from veins to lungs Moves oxygenated blood from lungs to arteries Valves and intrinsic electrical system keep blood moving in the right direction The heart itself has its own system of vessels Review of Anatomy of Arterial Wall of 4 Regions that you should know: 1) Endothelium 2) Intima 3) Media 4) Adventitia Endothelium Endothelium Single monolayer of cells between arterial wall and blood Normally non­thrombogenic (nothing sticks to it) Serves as a permeability barrier Regulates its own growth and function Intimal Layer of Intimal Layer of Arterial Wall Innermost layer of arterial wall closest to the blood This is where all the action takes place with respect to atherosclerosis Medial Layer of Medial Layer of Arterial Wall Middle layer of arterial wall Usual site of smooth muscle in arterial wall Only indirectly involved in atherosclerosis Adventitial Layer of Adventitial Layer of Arterial Wall Outermost layer of arterial wall Not really directly or indirectly involved in atherosclerosis Atherosclerosis – General Info Atherosclerosis Overview “Response to Injury” Hypothesis of Atherosclerosis First step: Development of Fatty Streak Second Step: Development of Fibrous Plaque Third Step: Development of Complicated Lesion Ross (1993) Nature Fatty Streak Formation #1 Fatty Damage to the Damage Endothelial layer Endothelial Primarily occurs at a Primarily bend in an artery (carotid or coronary arteries) arteries) RIVER LAMINAR FLOW TURBULENT FLOW TURBULENT FLOW CAROTID ARTERY BIFURCATION LAMINAR FLOW Fatty Streak Formation #2 Fatty Bends cause turbulent blood flow Bends that lead to vulnerable areas for endothelial injury endothelial High cholesterol, high blood High pressure, obesity, and smoking contribute to “injure” endothelium contribute Fatty Streak Formation #3 Fatty Originally believed endothelial layer was lost at site of “injury” Now it is known that this is not the case at this stage of the process “Injury” allows endothelial layer to “leak” chemicals through it Main chemical that “leaks” is LDL­C (low density lipoprotein cholesterol) LDL­C undergoes chemical changes and becomes trapped Fatty Streak Formation #4 Fatty Monocytes then enter between endothelial cells to digest modified LDL­C Form “foam cells” so called because of their appearance Foam cells lie under endothelial layer and give appearance of a fatty streak Smooth muscle cells migrate from media to intima Photograph: Imperial College London Fatty Streak Formation #5 Fatty Fatty streak may not proceed to Fibrous Plaque stage!!!!! Fatty streaks evident in children as young as 1 year old!!!!! May not alter size of the opening of the artery May make artery wall less smooth which increases the chance of other chemicals binding to it Review Review Overview of the process of atherosclerosis First The Fatty streak stage is the ______ stage in the process of atherosclerosis. Fatty streaks are caused by damage to the Endothelial ________ layer of the vessel. Fatty streaks and atherosclerosis tend to occur Bend Bifurcate where vessels _______ or ________. Monocytes Foam cells are created by _________ ingesting LDL the ________­C. Atherosclerosis Development Atherosclerosis Development Endothelial Damage Leaks chemicals & LDL­C LDL­C undergoes modification & is trapped Monocytes Enter Foam Cells formed Smooth Muscle Cells Migrate from media to intima Fibrous Plaque Development #1 Fibrous Plaque Development #1 Characterized by a fibrous cap Fibrous cap primarily composed of smooth muscle Also contains network of connective tissue May also contain dead cells and calcium deposits Doesn’t contain much lipid Layer below it contains foam cells Fibrous Plaque Development #2 Fibrous Plaque Development #2 Loss of endothelial layer is initial event in Fibrous Plaque Development Allows cells to directly adhere to inside of blood vessels Starts a chain reaction causing smooth muscle to migrate from media to intima Starts to decrease the open area of the blood vessel Complicated Lesion Formation #1 Formation Occurs when a Fibrous Plaque ulcerates or hemorrhages ulcerates Can be caused by the force of increased blood flow turbulence, hemorrhage within the plaque, or other chemical reasons or Complicated Lesion Complicated Formation #2 Formation Result is increased platelet binding and increased coagulation increased Three potential results – may dissolve without clinical effects, may be incorporated into and expand lesion, or may block artery and cause heart attack. attack. Progression of Heart Disease Progression of Heart Disease Coronary Angiogram Coronary Angiogram Coronary Artery Occlusion A A. Coronary artery occlusion B B. Same coronary artery after balloon angioplasty angioplasty This leads us to the topic of the rest of the This leads us to the topic of the rest of the course – RISK FACTORS FOR CARDIOVASCULAR DISEASE ...
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