cvs lec 1.pdf , cardiovascular system and pathology
- 2. ARTERIOSCLEROSIS • Arteriosclerosis (“hardening of the arteries”) is characterized by arterial wall thickening and may be caused by: 1. Arteriolosclerosis: It affects small arteries and arterioles . 2. Mönckeberg medial sclerosis: It is characterized by deposition of calcium in muscular arteries seen in old age (above 50 years). 3. Atherosclerosis: It is the most frequent and important disease of intima.
- 4. Definition • Atherosclerosis is the deposition of fibrofatty material in tunica intima of large to medium sized vessels
- 6. Major steps in atheroma formation Normal Endothelial injury/dysfunction with adhesion of monocyte Migration of monocyte into arterial intima and convert into macrophages They engulf lipoprotein and oxidized LDL to form foam cells Migration of smooth muscle followed by their proliferation in intima Fully developed atheromatous plaque
- 8. Atheroscclerosis • Microscopy Three main components in varying proportions in different lesions: 1. Cells: Smooth muscle cells, macrophages, and T-cells. 2. Extracellular matrix (ECM): Collagen, elastic fibers, and proteoglycans. 3. Lipid: Both intracellular and extracellular lipid
- 9. Fatty streaks • Gross feature Yellow flat macules • Microscopic Features Vaculated macrophages in tunica intima
- 10. Atherosclerotic plaque Gross features • white to yellow raised lesions • Eccenteric/focal on cut section of vessel Microscopic features Superficial fibrous cap →smooth muscle cells,dense collagen Lipid necrotic core→Extracellular lipid,intracellular lipid(foam cells),necrotic debris,thrombi and fibrin Additional features:Neovascularization and dystrophic calcification
- 13. Fatty steak
- 15. Major vessels involved in atherosclerosis in descending order are: • Lower abdominal aorta (abdominal aorta more than the thoracic aorta) • Coronary arteries • Popliteal arteries • Internal carotid arteries • Vessels of the circle of Willis.
- 16. Complications of atherosclerosis: • 1. Rupture • 2. Hemorrhage into the plaque • 3. Thrombosis • 4. Embolism • 5. Aneurysm • 6. Calcification.
- 19. Major clinical consequences of atherosclerosis
- 20. Aneurysm
- 24. Definition • An aneurysm is defined as a congenital or acquired, localized, abnormal, permanent dilation of a blood vessel or the heart
- 25. Morphological types of aneurysm: 1. Fusiform 2. Saccular 3. Cylindrical 4. Aortic dissection.
- 26. Microscopic features • Atheroseclrosis • Thinning of tunica media • Dilation plus thrombus • Inflammatory abdominal aortic aneurysm(lymphocyte,plasma cells,giant cells,fibrosis) • Mycotic aneurysm(infective endocarditis)
- 27. Predisposition Factors • 1.Atherosclerosis: It predisposes to aneurysms in the abdominal aorta. • 2. Hypertension: It predisposes to aneurysms of the ascending aorta • 3.Trauma • 4. Vasculitis • 5. Congenital defects (e.g. berry aneurysms in the circle of Willis)
- 28. • 6.Tertiary syphilis: It is a rare cause of aortic aneurysms. Trepenomas has affinity for vasa vasorum of mainly thoracic aorta obliterative endarteritis leads to ischemic damage to the aortic media and aneurysm (syphilitic mesoaortitis) • 7. Infections (mycotic aneurysms):
- 29. Causes of abdominal aorta aneurysm • Atherosclerotic AAA(most common cause) • Inflammatory AAA • Mycotic AAA
- 32. Gross • Tear in tunica intima • Double barreled aorta
- 33. Microscopic features Cystic Cystic space in tunica media Medial degeneration Smooth muscle cells dropout and necrosis Elastic tissue fragmentation Replaced by amorphous proteoglycan of ECM
- 36. Hypertention
- 39. Hypertensive vascular disease Small vessel disease Hyalin arteriosclerosis 1.Eosinophilic and hyaline material in intima media 2.Luminal narrowing Hyperplastic arteriosclerosis 1.Onion skin appearance 2.Concentric hyperplastic layers of smooth muscle Necrotising arteriolitis 1.Fibrinoid deposits 2.Vessel wall necrosis 3.macrophages Medium and large vessel disease 1.Atherosclerosis 2.Degenrative changes