KA7-Pathology of CVD Flashcards
What is atherosclerosis?
Atherosclerosis is the accumulation of fatty material (consisting mainly of cholesterol, fibrous material and calcium) forming an atheroma beneath the endothelium of an artery wall.
What are the effects of an atheroma on arteries and blood pressure?
As the atheroma grows the artery thickens and loses its elasticity, the diameter of the lumen becomes reduced and blood flow becomes restricted resulting in increased blood pressure.
What can atherosclerosis cause?
It is the root cause of various cardiovascular diseases such as angina, heart attack and peripheral vascular disease.
What is thrombosis?
This is the formation of a blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system.
State the process of thrombosis.
- Atheromas may rupture, damaging the endothelium.
- The damage releases clotting factors that activate a cascade of reactions resulting in the conversation of enzyme prothrombin to its active form thrombin.
- Thrombin causes molecules of the plasma protein fibrinogen to form threads of fibrin.
- The fibrin threads form a meshwork that clots the blood, seals the wound and provides a scaffold for the formation of scar tissue.
5.the formation of a clot (thrombus) is referred to as thrombosis.
What is an embolus?
When a thrombus may break loose forming an embolus which travels through the bloodstream until it blocks a blood vessel.
What happens if thrombosis occurs in a coronary artery?
It may lead to a myocardial infarction (MI), commonly known as a heart attack, because cells are deprived of oxygen leading to death of the tissues.
What happens if thrombosis occurs in an artery leading to brain?
A thrombosis in an artery in the brain may lead to a stroke, because cells are deprived of oxygen leading to death of the tissues.
What is peripheral vascular disease?
Peripheral vascular disease is the narrowing of the arteries due to atherosclerosis of arteries. All arteries are affected other than those of the heart or brain.
Which arteries are most commonly affected but peripheral vascular disease?
The arteries to the legs are most commonly affected.
What is experienced in the legs due to peripheral vascular disease?
Pain is experienced in the leg muscles due to a limited supply of oxygen.
What is deep vein thrombosis?
A deep vein thrombosis is a blood clot that forms in a deep vein, most commonly in the leg.
What can happen if the thrombus in a deep vein breaks off?
If a thrombus in a deep vein breaks off, then this can result in a pulmonary embolism in the lungs.
What is cholesterol?
Cholesterol is a type of lipid found in the cell membrane.
What is cholesterol used for?
It is used for to make sex hormones, testosterone, oestrogen and progesterone.
Who synthesises cholesterol?
Cholesterol is synthesised by all cells. 25% of total production takes place in the liver.
What can a high diet in fats lead to?
Increase in cholesterol levels in the blood.
What is the job of HDL?
To transport excess cholesterol from the body cells to the liver for elimination. This prevents accumulation of cholesterol in the blood.
What is the function of LDLs?
To transport cholesterol to body cells. However, it will deposit cholesterol inside arteries if the cells have enough cholesterol.
Why do LDLs deposit cholesterol in the bloodstream?
Because most cells have LDL receptors that take LDL into the cell where it releases cholesterol. When a cell has sufficient cholesterol, it switches on its negative feedback system, which inhibits the synthesis of new LDL receptors. This leads to LDLs continuing to circulate in the blood where it may deposit cholesterol in the arteries forming an atheroma.
Why does the ratio of HDL to LDL matter?
It matters because high levels of HDL will lower blood cholesterol and it will reduce the chance of atherosclerosis. Whereas it will be the opposite if we have high levels of LDLs than HDLs.
What are the benefits of regular physical activity?
Regular physical activity tends to raise HDL levels.
