1. What do I remember? What is thrombosis?
What effect does a ruptured atheroma have on thrombus formation?
What are the roles of thrombin, fibrinogen and fibrin in thrombus formation?
How is a thrombus different to an embolus?
What effect does a thrombosis have on the heart and brain?
What is peripheral vascular disease?
Describe two examples of peripheral vascular disease

2. Higher Human Biology Unit 2 Physiology and Health
3. Cholesterol and Familial cholesterolaemia

3. What do I need to know? What is cholesterol?
Where is cholesterol formed?
What is the function of cholesterol?
What causes an increase in blood cholesterol?
What’s the difference between HDL and LDL?
What is the role of LDL in atheroma formation?
What ratio of HDL to LDL is beneficial?
How can cholesterol levels be reduced?
What is familial cholesterolaemia and what is its effect?
How is familial cholesterolaemia treated?

4. What is cholesterol? Cholesterol is a sterol due to hydroxyl group
and its steroid rings
Part of family of compounds called lipids
Lipids are simple fats (saturated/unsaturated) and more complex steroids

5. Synthesis of cholesterol
Formed in all cells
25% of all cholesterol in body synthesised in liver from saturated fats gained from diet

6. Function of cholesterol
Synthesis of steroids
Cell membrane
Major component of cell
Without cholesterol membranes would be too fluid and too permeable to some substances membranes
Important in formation of steroids
It is a precursor molecule for many substances
E.g. steroid hormones
E.g. oestrogen and progesterone

7. What causes an increase in cholesterol?
A diet high in saturated fat causes an accumulation of cholesterol in the blood
A condition called familial hypercholesterolaemia also raises cholesterol levels

8. The difference between LDL and HDL?
Low density lipoproteins
Transports cholesterol to body cells
Most cells synthesise and insert LDL receptors in their plasma membranes
LDL-cholesterol binds to receptor
LDL-cholesterol engulfed by cell
Cholesterol released for use

9. Difference between LDL and HDL cont’d
If too much cholesterol: negative feedback occurs
Synthesis of LDL receptors inhibited
Less receptors less cholesterol taken up by body cells
More cholesterol in blood
Endothelial cells of arteries absorb some cholesterol
Leads to atheroma

10. High density lipoprotein
HDL
High density lipoprotein
Transports excess cholesterol from body cells to liver for elimination
Prevents accumulation of cholesterol in the blood
HDL-cholesterol not absorbed by arterial walls
Does not contribute to atherosclerosis
Higher ratio of HDL:LDL decreases blood cholesterol and reduces risk of cardiovascular disease

11. How can cholesterol levels be reduced?
Statins – inhibit synthesis of cholesterol in liver

12. What is familial hypercholesterolaemia?
Revision!!
What is meant by autosomal?
What is meant by dominant?
FH is an autosomal dominant disorder
Individuals predisposed to high cholesterol
Number of LDL receptors reduced/altered

13. How is familial hypercholesterolaemia treated?
Genetic testing can confirm diagnosis
Lifestyle modifications
E.g.?
Medication
Treatment designed to prevent early accumulation of cholesterol and increased risk of cardiovascular disease

14. What do I know? What is cholesterol? Where is cholesterol formed?
What is the function of cholesterol?
What causes an increase in blood cholesterol?
What’s the difference between HDL and LDL?
What is the role of LDL in atheroma formation?
What ratio of HDL to LDL is beneficial?
How can cholesterol levels be reduced?
What is familial cholesterolaemia and what is its effect?
How is familial cholesterolaemia treated?

15. Activities
Testing your knowledge Qs p186 No. 3