2.7. Pathology of Cardiovascular Disease (CVD) Flashcards
What is atherosclerosis?
This is the fatty accumulation of substances (cholesterol, fibrous material and calcium salts) forming an atheroma beneath the endothelium of an artery’s wall. As an atheroma grows the artery becomes thicker and loses elasticity. The lumen grows narrower and restricts blood flow which in turn increases blood pressure.
What can atherosclerosis cause?
Angina, heart attack, stroke and PVDs.
What are the main causes of atherosclerosis?
Diabetes, high blood pressure, smoking and a history of CVD in the family.
What is thrombosis?
If an atheroma ruptures, the damage done to the endothelium of the artery causes the release of clotting factors. A series of reactions occur changing the enzyme prothrombin into thrombin. Thrombin causes fibrinogen in the blood to form threads of insoluble fibrin proteins. These proteins then form a mesh which traps platelets and red blood cells forming a clot. A thrombus in a coronary artery can lead to heart attack. A thrombus in a brain artery can cause stroke.
What is an embolism?
If a thrombus breaks loose it forms an embolus. These travel through the bloodstream and can blood blood vessels which leads to cell oxygen deprivation. Tissues can die of this.
What does PVD stand for and what is an example of one?
PVD = Peripheral Vascular Disorder, these are the narrowing of arteries due to atheromas in arteries other than those to the heart or brain.
An example would be deep vein thrombosis, this is the formation of a thrombus in a deep vein and is most commonly found in the lower leg.
Another example could be a pulmonary embolism which the an embolus forming and travelling to the pulmonary artery. Blockages can form here causing breathing difficulties.
What does HDL stand for and what do they do?
HDL = High-Density Lipoprotein
They transport excess cholesterol from body cells to the liver for elimination to prevent the accumulation of cholesterol in the blood.
What does LDL stand for and what do they do?
LDL = Low-Density Lipoprotein
They transport cholesterol to the body cells. Most cells have LDL receptors that take LDL into the cell where it releases its cholesterol. Once it receives sufficient cholesterol, a negative feedback inhibition occurs so the LDLs continue to circulate the body. They can deposit cholesterol in the arteries forming atheromas.
What is the better HDL to LDL ratio?
High HDL to LDL ratios are better.
What is familial hypercholesterolaemia?
An autosomal dominant disorder causing high blood pressure. It results in a decreased number of LDL receptors. Treatment includes lifestyle modification.
What lifestyle choices can affect HDL to LDL ratios?
Physical activity raises HDL:LDL ratio as well as low-fat diets. Medicines like statin also inhibit the synthesis or cholesterol.
