Physiology and Health: Pathology of Cardiovascular Disease (CVD) Flashcards
What is atherosclerosis?
The accumulation of fatty material (consisting mainly of cholesterol), fibrous material and calcium, forming an atheroma or plaque beneath the endothelium
Where does an atheroma form?
Beneath the endothelium (inner lining) of the artery wall
What happens as an atheroma grows?
The artery thickens and loses its elasticity
An atheroma reduces diameter of the lumen of an artery, which does what?
Restricts blood flow and results in increased blood pressure
Atherosclerosis is the root cause of various cardiovascular diseases (CVD), what are they?
Angina, heart attack, stroke and peripheral vascular disease
Atheromas may rupture, doing what?
Damaging the endothelium
Damage to the endothelium does what?
Releases clotting factors that activate a cascade of reactions, resulting in the conversion of the inactive enzyme prothrombin to its active form thrombin
Thrombin causes what?
Molecules of the plasma protein fibrinogen to form threads of fibrin
What do the fibrin threads form?
A meshwork that clots the blood, seals the wound and provides a scaffold for the formation of scar tissue
The formation of a clot (thrombus) is referred to as what?
Thrombosis
In some cases, a thrombus may break loose, forming an embolus which does what?
Travels through the bloodstream until it blocks a blood vessel
A thrombosis in a coronary artery may lead to what?
Myocardial infarction (MI), commonly known as a heart attack
A thrombosis in an artery in the brain may lead to what?
A stroke
Thrombosis normally results in what?
The death of some of the tissue served by the blocked artery as the cells are deprived of oxygen
What is peripheral vascular disease and where is the most commonly affected place?
The narrowing of the arteries due to atherosclerosis of arteries other than those of the heart or brain. The arteries to the legs are most commonly affected
What is a deep vein thrombosis (DVT)?
A blood clot that forms in a deep vein, most commonly in the leg
What happens in DVT?
Pain is experienced in the leg muscle due to a limited supply of oxygen
A pulmonary embolism is caused by what?
Part of a thrombus breaking free and travelling through the bloodstream to the pulmonary artery, where it can cause a blockage, resulting in chest pain and breathing difficulties
What is cholesterol?
A type of lipid found in the cell membrane
What is cholesterol also used in?
Making the sex hormones testosterone, oestrogen and progesterone
Cholesterol is synthesised by all cells although 25% of total production takes place where?
In the liver
A diet that is high in saturated fats or cholesterol causes what?
An increase in cholesterol level in the blood
Lipoproteins contain what?
Lipid and protein
What does high density lipoprotein (HDL) do?
Transports excess cholesterol from the body cells to the liver for elimination preventing accumulation of cholesterol in the blood
What does low density lipoprotein (LDL) do?
Transports cholesterol to body cells
Most cells have LDL receptors which do what?
Take LDL into the cell where it releases cholesterol
Once a cell has sufficient cholesterol, what happens?
A negative feedback system inhibits the synthesis of new LDL receptors and LDL circulates in the blood where it may deposit cholesterol in the arteries forming atheromas
A higher ratio of HDL to LDL results in what?
Lower blood cholesterol and a reduced chance of atherosclerosis
Regular physical activity tends to do what?
Raise the HDL level
Dietary changes aim to do what?
Reduce the level of total fat in the diet and to replace saturated with unsaturated fats
What do drugs such as statins do?
Reduce blood cholesterol by inhibiting the synthesis of cholesterol by liver cells
