Unit 2- Cardiovascular Disease

Question 1

Describe the process of atherosclerosis.

Answer 1

1. Atherosclerosis is the accumulation of fatty material (consisting of cholesterol, fibrous material and calcium) forming an atheroma or plaque beneath the endothelium.
2. As the atheroma grows the artery thickens and loses its elasticity. The diameter of the lumen becomes reduced and blood flow becomes restricted, increasing blood pressure.

Question 2

Describe thrombosis.

Answer 2

1. The formation of a clot (thrombus) is called thrombosis.
2. Atheroma’s may rupture damaging the endothelium.
3. The damage releases clotting factors that activate a cascade of reactions resulting in the conversion of the enzyme prothrombin to its active form thrombin.
4. Thrombin causes molecules of fibrinogen to form threads of fibrin.
5. Fibrin threads form a meshwork that clots the blood, seals the wound and provides a scaffold for the formation of scar tissue.
6. A thrombus could break loose forming an embolus which travels the bloodstream until it blocks a vessel.
7. A thrombosis in a coronary artery may lead to a heart attack.
8. A thrombosis in an artery in the bran may lead to a stroke as cells are deprived of oxygen and die.

Question 3

Describe peripheral vascular disease

Answer 3

This is the narrowing of the arteries due to atherosclerotic of arteries. Most common in legs.

Question 4

Describe a Deep Vein Thrombosis

Answer 4

This is a blood clot in a deep vein, common in the legs, which can break off and result in a pulmonary embolism in the lungs.

Question 5

What is cholesterol?

Answer 5

A lipid found in cell membrane. Made in all cells. 25% made in liver.

Question 6

What increase cholesterol levels?

Answer 6

High and saturated fats.

Question 7

What is the role of HDL? (High Density Lipoprotein)

Answer 7

Transport excess cholesterol from the body cells to liver for elimination preventing the accumulation of cholesterol.

Question 8

What is the role of LDL? (Low Density Lipoprotein)

Answer 8

Transport cholesterol to body cells. Cells have LDL receptors and take LDL into the cell where it releases cholesterol.

Question 9

Describe the negative feedback of LDL and cholesterol.

Answer 9

Once a cell has sufficient cholesterol the synthesis of new LDL Receptors is inhibited and LDL circulate in the blood wheee it may deposit cholesterol forming atheromas.

Question 10

What does a higher ratio of HDL to LDL do?

Answer 10

Results in lower blood cholesterol and a reduced chance of atherosclerosis.

Question 11

What raises HDL levels?

Answer 11

Regular physical activity.

Question 12

What drug reduce blood cholesterol?

Answer 12

Statin.