Cardiovascular Pathology Flashcards
what are some lifestyle choices that can cause atherosclerosis?
- smoking
- obesity
- lack of exercise
- diet
what are some non-modifiable factors that may contribute to atherosclerosis?
- age
- gender
- genes
what is high blood cholesterol known as?
hyperlipidaemia
what is atherosclerosis?
a chronic inflammatory response followed by the healing response
how is an atheroma formed?
- presence of cholesterol in the vessel walls initiates a chronic inflammatory response
- the healing response is triggered
- this causes formation of fibrous tissue
what is vascular pathology?
either stenosis/obstruction or weakening of the vessel walls leading to dilation/rupture
what genetic condition may make a patient more likely to develop atherosclerosis?
familial hypercholesterolaemia (mutation of LDL receptor gene)
what is the normal state of an endothelial cell known as?
basal state
what is the pathological state of an endothelial cell known as?
activated state
explain the structure of basal state endothelial cells:
- surface is smooth & non-adhesive (inflammatory cells cannot attach and aggregate on the surface)
- non-thrombocytic (cannot induce activation of the coagulation system)
explain the structure of an activated endothelial cell:
- surface of endothelial cell becomes changed because of cytokines, bacterial toxins, lipid products… inflammatory cells adhere to the surface of cells
- permeability changes and inflammatory cells can move in
- vasoactive substances are released causing vasoconstriction/vasodilation
what are the two phases of a forming atheroma?
inflammation phase and healing phase
what occurs during the chronic inflammation phase of atheroma formation?
- endothelial cells change surface cell receptors & become more permeable to lipids
- altered cell adhesion molecules so monocytes (macrophages and T cells) attach to endothelium & move into blood vessel wall
- macrophages are phagocytes and engulf the lipid present in the tunica intima
what occurs when macrophages engulf lipids?
- enlarged size
- pale colour
- known as FOAM CELLS
what occurs during the healing phase of a forming atheroma?
- proliferation of smooth muscle cells and fibrous tissue in the tunica intima
- macrophages produce IL-1 which activates T cells
- more cytokines & chemokines activate inflammatory cells
- fibrous tissue formation over the lipid & a fatty atheroma (plaque) is formed
what are the resulting effects of atheroma formation?
- ischemia
- infarction
- thrombosis
- embolism
what is ischemia?
decreased blood supply to tissue/organ
what is infarction?
complete occlusion of a blood vessel leads to tissue necrosis
what is thrombosis?
damage of endothelial cells or plaque rupture which causes triggering of the clotting cascade to form a thrombus on the plaque
what is meant by embolism?
thrombus breaks off and travels in the blood stream
how can chronic periodontitis lead to atheroma formation?
- inflammation and the biofilm will result in the presence of growth factors & cytokines in the circulation
- invitation of an acute phase response in the production of c-reactive protein by the liver
what is peripheral vascular disease?
ischemia in the muscles of the lower legs
what may occur due to peripheral vascular disease?
- claudication = pain and cramps
- gangrene = complete obstruction of the arteries leading to necrosis of muscles
- coagulation necrosis and infection due to anaerobic bacteria
what is an aneurysm?
an abnormal dilation in the wall of a blood vessel
what are the main causes of an aneurysm?
- developmental = inherited condition
- degenerative = infection with mycotic infections or syphilis
- traumatic = atherosclerosis
what occurs in the vessel wall that leads to an aneurysm?
- macrophages (present due to inflammation) produce matrix metalloproteinases
- MMPs degraded the fibrous tissue leading to weakening of the blood vessel wall
- this leads to abnormal dilation and an increase in size
what occurs during a myocardial infarction?
- myocytes switch to anaerobic respiration to supply energy to the muscles (ineffective)
- coagulation necrosis of myocardial muscle then occurs
how does the cardiac tissue heal after a myocardial infarction?
by formation of granulation tissue
- impaired heart function
what are tumours of the blood vessels?
- hamartomas
- kaposi sarcoma
what are hamartomas?
- collection of cells that are normal but increased in size
- non-malignant
- no connective tissue capsule surrounding these structures (normally found in benign tumours)
who is most likely to suffer from Kaposi Sarcomas?
patients with advanced HIV infection
what is the aetiology of kaposi sarcomas?
Herpes virus 8
what is a haemangioma?
hamartoma of the endothelial cells (commonly seen in head & neck)
what are examples of benign cardiac tumours?
- myxoma
- lipoma
what is an example of a malignant cardiac tumour?
angiosarcoma
what can pathology of heart valves lead to?
- stenosis (failure of valve to open completely)
- insufficiency (failure of valve to close properly)
- vegetations (nodules on the endocardium & valve that may be thrombocytic or infective)
what is the most common valve condition?
calcification aortic stenosis
what occurs to a patient suffering from calcific aortic stenosis?
- dystrophic calcium deposits (result of chronic endothelial injury)
- narrowing of the valvular orifice which affects valve function
what type of reactions are involved in rheumatic heart disease?
- type 2 (cytotoxic type of fibrous sensitivity reaction)
- type 4 (cell-mediated T cell reaction)
