Unit 2 - Pathology of Cardiovascular Disease Key Area 7 Flashcards
What is arterosclerosis
Atherosclerosis is the accumulation of fatty
material (consisting mainly of cholesterol,
fibrous material and calcium) forming an
atheroma or plaque beneath the
endothelium.
What effect does arterosclerosis have on the artery 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 cardiovascular diseases does artherosclerosis cause?
Atherosclerosis is the root cause of various
cardiovascular diseases (CVD) — angina,
heart attack, stroke and peripheral vascular
disease.
How is thrombin formed?
Atheromas may rupture damaging the
endothelium. The damage releases clotting
factors that activate a cascade of reactions
resulting in the conversion of the enzyme
prothrombin to its active form thrombin.
What does thrombin cause
Thrombin causes molecules of the plasma
protein fibrinogen to form threads of fibrin.
What does the fibrin thread form?
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 thrombosis.
What can happen if a thrombus breaks lose?
In some cases a thrombus may break loose
forming an embolus which travels through
the bloodstream until it blocks a blood vessel.
What might a thrombosis in a coronary artery lead to?
A thrombosis in a coronary artery may lead
to a myocardial infarction (MI), commonly
known as a heart attack. A thrombosis in an
artery in the brain may lead to a stroke. Cells
are deprived of oxygen leading to death of
the tissues.
What is peripheral vascular disease and what does it cause?
Peripheral vascular disease is 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. Pain is experienced in the leg
muscles due to a limited supply of oxygen.
What is a deep vein thrombosis (DVT)
A deep vein thrombosis (DVT) is a blood clot
that forms in a deep vein, most commonly in
the leg. This can break off and result in a
pulmonary embolism in the lungs.
What is cholestrol and does it do?
Cholesterol is a type of lipid found in the cell
membrane. It is also used to make the sex
hormones — testosterone, oestrogen and
progesterone.
How is cholestrol synthesised?
Cholesterol is synthesised by all cells,
although 25% of total production takes place
in the liver. .
What does HDL do?
HDL transports excess cholesterol from the
body cells to the liver for elimination. This
prevents accumulation of cholesterol in the
blood.
What does LDL do?
LDL transports cholesterol to body
cells.
a) Describe LDL receptors?
b) Describe negative feedback ihibition?
c) Describe how a atheromas is formed?
a) Most cells have LDL receptors that take LDL
into the cell where it releases cholesterol.
b) Once a cell has sufficient cholesterol a
negative feedback system inhibits the
synthesis of new LDL receptors and LDL
c) circulates in the blood where it may deposit
cholesterol in the arteries forming atheromas.
