Biology

• what does the fatty material consist of?

  cholesterol, fibrous material and calcium
• what happens as the atheroma grows?

  the artery thickens and loses its elasticity
• what does the artery thickening and losing the elasticity mean?

  the diameter of the lumen

  decreases and blood flow becomes restricted
• what happens when blood flow becomes restricted?

  results in increased blood pressure
• Atherosclerosis is the root cause of

  various cardiovascular diseases (CVD)

  including..?

  angina, heart attack, stroke, peripheral vascular disease
• What is thrombosis?


  Atheromas may rupture and damage the endothelium of the

  artery wall
• what does damage to the endothelium do?

  releases clotting factors
• what reactions do the clotting factors activate?

  Prothrombin (an inactive enzyme) is converted to thrombin

  (the active form) and Thrombin causes fibrinogen (a plasma protein) 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
• what is the formation of a clot referred to as?

  thrombosis
• what happens if a thrombus breaks loose from the blood vessel wall?


  forms an embolus
• what does the embolus do?

  it travels through the bloodstream until it blocks a blood vessel
• what can a thrombosis in a coronary artery lead to?

  a myocardial infarction (MI), commonly known as a heart attack
• what can a thrombosis in an artery in the brain lead to?

  stroke
• in both cases, what are cells deprived of?

  oxygen leading to death of the tissues
• what is peripheral vascular disease?

  narrowing of arteries (other

  than those of the heart or brain) due to atherosclerosis
• what arteries are most commonly affected by pvd?


  legs
• Why is pain experienced in the leg muscles?

  due to a limited supply of oxygen
• What is deep vein thrombosis?

  a blood clot that forms in a deep vein, most commonly in the leg
• What can DVT lead to?

  pulmonary embolism in the lungs
• What is cholesterol?


  a type of lipid found in the cell membrane
• what sex hormones is cholesterol used to make?

  testosterone, oestrogen and progesterone
• cholesterol is synthesised by all cells however...?

  25% of total production takes place in the liver
• what can a diet which is high in saturated fats or cholesterol cause?

  an increase in cholesterol levels in the blood
• what are the two types of lipoproteins?

  high density lipoproteins and low density lipoproteins
• What does HDL transport?


  excess cholesterol from the body cells to the liver for elimination
• what does this prevent?

  accumulation of cholesterol in the blood
• What does LDL transport?

  cholesterol to body cells.
• What do most cells have?

  LDL receptors and so low density lipoproteins are taken into the cell and cholesterol is released inside the cell
• what happens once a cell has a sufficient cholesterol?

  a negative feedback system

  inhibits the synthesis of new LDL receptors
• what else happens once a cell has sufficient cholesterol?

  also means that LDL then

  circulates in the blood and may deposit cholesterol in the arteries.
• what does cholesterol may then form?

  atheromas
• what does having a higher ratio of HDL to LDL result in?

  lower blood cholesterol
• what does having low blood cholesterol mean?

  the chance of atherosclerosis will be reduced
• what can regular physical activity raise?

  HDL levels and so lowers cholesterol levels in the blood
• why are dietary changes made?

  to reduce the levels of total fat

  in the diet and replace saturated fats with unsaturated fats
• what does drugs such as statins reduce?

  blood cholesterol levels by

  inhibiting the synthesis of cholesterol by liver cells
• what does chronic elevation of blood glucose levels lead to?

  cells in the endotheloum taking in more glucose than normal
• what does this damage?

  the blood vessels
• what may develop because of this?

  atherosclerosis