pathology of cardiovascular disease Flashcards
atherosclerosis is the
accumulation of fatty material, fibrous material and calcium, forming an atheroma or plaque
An Atheroma forms beneath the endothelium (inner lining) of
of the artery wall
as an atheroma grows, the artery
thickness and loses its elasticity
an atheroma reduces the diameter of lumen of an artery,which
restricts blood flow and results in increased blood pressure
atherosclerosis is the root cause of various cardiovascular diseases such as:
angina
heart attack
stroke
peripheral vascular disorders
if an atheroma ruptures , the damage to the endothelium causes
clotting factors
clotting factors cause the enzyme prothrombin to be converted
into its active form thrombin
thrombin causes molecules of the double plasma protein fibrinogen to form
into its active form thrombin
Fibrin threads form a meshwork that paletes adhere to , forming a blood clot, which
seals a wound and provides a scaffold for the formation of scar tissue
thrombosis formation of
blood clot in a vessel
if thrombosis breaks loose it forms
embolus
thrombosis in a coronary artery can lead to a
myocardial infarction
thrombosis in an artery in the brain can lead to a
stroke
thrombosis normally results in the death of some of the tissue served by the blocked artery as the cells are
deprived of oxygen
peripheral vascular disorder include narrowing of arteries due to atherosclerosis of arteries other than those of
the heart or brain
blood clots can result in
deep vein thrombosis (DVT) and pulmonary embolism
DVT is the formation of a blood clot in deep vein, most commonly in the
lower part of the leg
in DVT pain is experienced in the leg muscles due to a limited
supply of oxygen
a pulmonary embolism is caused by part of a thrombus breaking free and travelling through the bloodstream to the pulmonary artery,where it can cause
blockage, resulting in chest pain and breathing difficulties
cholesterol is composed of cell membrane and a precursor for
steroids synthesis
mos cholesterol is synthesised by the liver from
saturated fats in the diet
lipoproteins
contain lipid and protein
high-density lipoproteins (HDL) transports cholesterol from the body cells to the liver for elimination and
so prevents the accumulation of cholesterol in the blood.
low density lipoprotein LDL transports
cholesterol to the body cells
most cells have LDL receptors that take LDL into the cell, where it
releases cholesterol
once a cell has sufficient cholesterol,
a negative feedback system inhibits the synthesis of new LDL receptors and so LDL circulates in the blood, which could cause atheromas
familial hypercholesterolaemia (FH) is caused by an
autosomal dominant allele that results in individuals developing high levels of cholesterol
The mutated gene involved in FH results in a decreased number or altered structure of …….
which stops the LDL from unloading its …..
LDL receptors on cell membranes,
cholesterol into a cell
genetic screening can be carried out to determine if the FH gene has been
inherited
treatment of FH involves lifestyle modification and drugs such as
statins
higher ratio of HDL to LDL results in
lower blood cholesterol and a reduced chance of atherosclerosis
regular physical activity tends to raise
HDL levels
dietary changes aim to reduce the levels of total fat in the diet and to the replace
saturated with unsaturated fats
drugs such as stains reduce blood cholesterol by inhibiting the synthesis of cholesterol by
liver cells
