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Pathology of Cardiovascular Disease (CVD) - Coggle Diagram
Pathology of Cardiovascular Disease (CVD)
Atherosclerosis
Atherosclerosis is the build-up of fatty material (cholesterol, calcium and fibrous material)
The build-up forms an atheroma under the endothelium
An atheroma lead to:
blockage restricts blood flow due to decreased diameter of the lumen
the restricted blood flow increases pressure
the artery loses its elasticity
Atherosclerosis can lead to CVD's such as angina, heart attack, stroke and peripheral vascular disease (PVD)
Blood Clotting
If the atheroma ruptures it can damage the endothelium of the artery which can lead to a blood clot
Formation of Blood Clot
2.
clotting factors convert the enzyme prothrombin to thrombin
3.
thrombin causes the plasma protein fibrinogen to form threads of fibrin
1.
damage to the endothelium releases clotting factors
4.
fibrin threads mesh together clotting the blood and sealing the wound
5.
scar tissue forms on the scaffold creating a clot
Thrombosis is the formation of the blood clot (thrombus) inside the blood vessel
If the thrombus breaks lose it from an embolus which travels in the bloodstream where it may block the blood vessel completely
If the embolus blocks the coronary artery it may lead to a heart attack (myocardial infection) or a stroke if it blocks an artery supplying the brain.
Tissue death may occur if there is a lack of oxygen
Peripheral Vascular Disease (PVD)
PVD is caused by the narrowing of arteries that are not connected to the heart or brain due to atherosclerosis
Arteries in the legs can be affected - pain may be felt in the legs due to lack of oxygen reaching the muscle cells
Deep vein thrombosis is a blood clot that forms in a deep vein, commonly in the leg. The blood clot could break off to form an embolus and could cause a pulmonary embolism
Cholesterol
Cholesterol is a type of lipid found in the cell membrane, also used to synthesis sex hormones
High cholesterol can cause CVD and high levels can be a result of a diet of high saturated fats of cholesterol
Cholesterol is produced by all cells but 25% is produced by the liver
There are two types of cholesterol carrying proteins
HDLs are high-density lipoproteins that transport excess cholesterol from the body to the liver for elimination from the body
LDLs are low-density lipoproteins that transport cholesterol from the liver to the rest of the body and deposit cholesterol inside the arteries
Cholesterol levels are controlled by a negative feedback system
1.
cells have LDL receptors on their surface which allow cholesterol to be deposited inside the cells by LDL's
2.
once there is enough LDL inside the cells, synthesis of new LDL receptors are inhibited which reduces the amount of cholesterol that is absorbed into the cells
3.
excess LDL carried cholesterol is deposited inside the arteries, lining the endothelium causes an atheroma to be formed
Controlling cholesterol levels
A higher ratio of HDL to LDL will result in lower blood cholesterol levels and will reduce chances of developing an atherosclerosis
A diet low in saturated fats and regular physical activity can raise HDL levels
Can also manage cholesterol levels with medication - statins reduce blood cholesterol levels by inhibiting synthesis of cholesterol in the liver