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Atherosclerosis

Atherosclerosis. The Arterial Wall. www-ermm.cbcu.cam.ac.uk/nfig003jal.gif. Cross-section of an Arterial Wall. Yellow Streak. http://www.surrey.ac.uk/SBMS/MicrobialSciences/research/immunology.html. Development of Fibrous Plaque. The Metabolic Syndrome.

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Atherosclerosis

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  1. Atherosclerosis

  2. The Arterial Wall www-ermm.cbcu.cam.ac.uk/nfig003jal.gif

  3. Cross-section of an Arterial Wall

  4. Yellow Streak

  5. http://www.surrey.ac.uk/SBMS/MicrobialSciences/research/immunology.htmlhttp://www.surrey.ac.uk/SBMS/MicrobialSciences/research/immunology.html

  6. Development of Fibrous Plaque

  7. The Metabolic Syndrome 1. Abdominal obesity (waist circumference >40 inches for men, 35 inches for women) 2. Triglyceride levels >150 mg/dL 3. HDL cholesterol <40 mg/dL for men, <50 mg/dl for women 4. Blood pressure >130>85 mmHg (normal is about 120/80) 5. Fasting blood glucose >110 mg/dL (normal is 100 mg/dL)

  8. Ischemic Heart Disease A mismatch between oxygen demand and oxygen delivery

  9. What influences O2 Delivery? • O2 carrying capacity of blood. • Coronary blood flow • Influenced by neural, endothelial and metabolic factors • Can be compromised by atherosclerosis

  10. What influences the myocardial O2 demand? • Heart Rate – Inc. HR inc. O2 demand • Cardiac contractility – Inc. contractility inc. O2 demand • Ventricular wall stress – proportional to afterload and the radius of ventricle => Law of Laplace

  11. Law of LaPlace • The ventricular wall stress (T) is the energy required to pull the cardiac muscle fibers together, so that they can contract. • Tension is proportional to the product of Intraventricular pressure (P), (which = afterload) and Radius of ventricle (R) • So, the greater the volume of the ventricle, the more energy required for contraction.

  12. What enlarges the volume of the ventricle? • A large blood volume (preload) => increase EDV, distends the ventricle • Ventricular dilation – a pathologic condition

  13. Manifestations of ischemia • Angina chest pain associated with intermittent myocardial ischemia. • Myocardial infarction (MI) is irreversible necrosis of cardiac muscle cells resulting from a prolonged period with of insufficient myocardial blood flow.

  14. http://www.smbs.buffalo.edu/pth600/IMC-Path/images/yr2/Coronary_Thrombosis_Schematic-Robbins.jpghttp://www.smbs.buffalo.edu/pth600/IMC-Path/images/yr2/Coronary_Thrombosis_Schematic-Robbins.jpg

  15. Vulnerable plaques are most likely to rupture, causing a myocardial infarction or a stroke

  16. Pathophysiology of Heart Disease 3/e. Leonard S. Lilly, Ed. Lippincott Williams and Wilkins. 2003

  17. Serum Markers of Myocardial Infarction Pathophysiology of Heart Disease 3/e. Leonard S. Lilly, Ed. Lippincott Williams and Wilkins. 2003

  18. Sudden Cardiac Death aka: Cardiac arrest • Often triggered by cardiac arrhythmia, which prevents the heart from contracting effectively. • Cause is often coronary artery disease. • Death of muscle tissue can make the heart more vulnerable to the type of arrhythmia that leads to SCD.

  19. There are two types of strokes • Ischemic or occlusive strokes, which occur when a portion of the blood flow to the brain is blocked. • Intracranial hemorrhages occur when a blood vessel in the brain ruptures.

  20. A Complete Circle of Willis Protects Against Stroke

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