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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
4 Regions that you should know:
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
Damage to the
Primarily occurs at a
bend in an artery
(carotid or coronary
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 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
Overview of the process of atherosclerosis
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
where vessels _______ or ________.
Monocytes Foam cells are created by _________ ingesting LDL
the ________C. Atherosclerosis Development
Endothelial Damage Leaks chemicals & LDLC
LDLC undergoes modification & is trapped
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
Occurs when a Fibrous Plaque
ulcerates or hemorrhages
Can be caused by the force of
increased blood flow turbulence,
hemorrhage within the plaque,
or other chemical reasons
or Complicated Lesion
Result is increased platelet binding and
Three potential results – may dissolve
without clinical effects, may be
incorporated into and expand lesion,
or may block artery and cause heart
attack. Progression of Heart Disease
Progression of Heart Disease Coronary Angiogram
Coronary Angiogram Coronary Artery
A. Coronary artery occlusion B
B. Same coronary artery after balloon
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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- Spring '08