Atherosclerosis

Question 1

What is atherosclerosis?

Answer 1

The build up of plaque and hardening of arteries that leads to coronary heart disease (CHD).

Question 2

Describe the process of blood clotting.

Answer 2

1. Endothelial layer in blood vessel becomes damaged.
2. This triggers an inflammatory response.
3. Platelets are activated and gather at damaged vessel (platelet plug)
4. Prothrombin is converted into thrombin
5. Fibrinogens are activated and converted into fibrin
6. Long soluble strands of fibrin mesh together to trap red blood cells and form a clot.

Question 3

How is fibrinogen converted into fibrin?

Answer 3

Prothrombin in converted into thrombin, by thromboplastin (enzyme), and catalyses the conversion of fibrinogen into fibrin.

Question 4

Describe how an atheroma is formed.

Answer 4

1. Endothelial layer becomes damaged because of high blood pressure.
2. Trigger inflammatory response. White blood cells move to artery wall. Cells accumulate chemicals, especially cholesterol. This causes an atheroma to build up
3. Plaque builds on inner artery wall due to calcium salts and fibrous tissue
4. This leads to loss of elasticity of artery.
5. Positive feedback response- lumen size decrease (artery narrows) so blood pressure is raised. Increases chances of arterial damage so process will happen again.