Pathophysiology of IHD
Abbreviation/definition;
• CHD = coronary heart disease
• IHD = ischemic heart disease
• ACS = acute coronary syndrome
• MI = myocardial infarction
• Ischemia = to suppress or withhold blood flow
Why ischemia happens?
• Increase oxygen demand --> high metabolic demand
• Decrease oxygen supply --> narrowing
Cholesterol and Triglyceride transport
Colour of boxes represents:
• Yellow contains cholesterol
• Blue contains triglyceride
• White contains both cholesterol and triglyceride
* Red arrow represents explanation of CHD
Hypothesis of plaque formation:
• Injury to the endothelial vessel layer, due to:
o Smoking
o Immune mechanism
o Mechanical stress --> hypertension
o Turbulent flow
Determinant of plaques vulnerability to rupture:
• Size of lipid core and stability and thickness of fibrous cap
• Presence of inflammation with plaque degradation
• Lack of smooth muscle cells with impaired healing and plaque stabilization
Site of atherosclerosis in order of frequency
1. abdominal aorta and iliac arteries
2. proximal coronary arteries
3. thoracic aorta, femoral and popliteal arteries
4. internal carotid arteries
5. vertebral basilar and middle cerebral arteries
Lipoprotein
1. chylomicrons - synthesize in intestine and transport dietary;
• triglygeride (adipose and skeletal muscle tissue)
• cholesterol (taken up by liver to form VLDL or secreted by bile)
2. LDL ;
• Main carrier of cholesterol
• LDL is mainly removed by receptor dependent pathway (mainly hepatocytes
• Also remove by non-receptor-dependent mechanism (scavenger cells)
o Can result in formation of foam cells
3. HDL ;
• Reverse transport of cholesterol; ie transport cholesterol from peripheral tissues to the liver to be excreted
1 Response to Pathophysiology of IHD
the posting is very brief. i will explain later during pbl. the pictures are not that clear. i've email a softcopy to everyone just in case.
yazid
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