2.7 Pathology of Cardiovascular Disease (CVD)

Define atherosclerosis

formation of atheroma beneath endothelium lining in arteries walls

What is an atheroma

plaques formed of cholesterol, calciums, fibrous materials

State the effect of atheroma on arteries

loses its elasticity overtime, thicken its walls, narrow the lumen

State the outcome of atherosclerosis

increased blood pressure due to narrowing of the lumen, increased risk of myocardial infarction (heart attack), stroke, angina, peripheral vascular disease

Why do atherosclerosis not occur in veins

low pressure environment

State the inactive enzyme and its activated form when clotting factors are released

prothrombin to thrombin

State the purpose of enzyme thrombin

convert fibrinogen (soluble protein) to fibrin (insoluble protein)

State purpose of fibrin

form meshwork for formation of scar tissue

State the term describing the process of blood clotting

thrombosis

State another name for blood clot

thrombus

State the name for a loose piece of thrombus

embolus

State the consequence of embolus on bloodflow

blocks narrow vessel - restrict or block bloodflow
if in coronary arteries - myocardial infarction
if in carotid arteries - stroke

What are the peripheral arteries

all arteries except the aorta, coronary arteries, carotid arteries

Define peripheral vascular disease

narrowing of peripheral arteries due to atherosclerosis

Where does peripheral vascular disease usually affect

leg arteries

Define deep vein thrombosis

formation of a thrombus in a deep vein (usually in lower leg)

State symptoms of DVT in lower leg

pain, swollen surface veins - lumpy surface

Define cholesterol

type of lipid found in all cells

State purpose of cholesterol

synthesis sex hormons (progesterone, oestrogen, testosterone)

Where is cholesterol synthesised

all cells, 25% in liver from saturated fats

State 2 types of cholesterol

low density lipoproteins (LDL), high density lipoproteins (HDL)

Define lipoproteins

molecules made up of lipid and protein, and used to transport lipids around the body

Where is LDL produced

liver

How is LDL cholesterol absorbed in cells

via LDL receptors in cell membrane
1. cell engulf LDL cholesterol with its receptor
2. cholesterol is used
3. new receptor created

How is cholesterol level in cells maintained

negative feedback
cells inhibit the synthesis of new LDL receptors when the cholesterol supply is adequate

State the outcome of the inhibition of the synthesis of new LDL receptors

cholesterol level in blood increase - deposited in atheromas

State the function of HDL

transport excess cholesterol in bloodstream for excretion in the liver in the form of bile, does not contribute to atherosclerosis

State the average ratio of LDL to HDL

70% to 30%

State 3 methods to increase concentration of HDL

regular physical activity, low fat diet, medications (eg statins - inhibits synthesis of cholesterol by liver cells)