T1L5 Blood Clotting and Atherosclerosis

Question 1

Describe the process of Myocardial Infarction

Answer 1

1) A plaque made of cholesterol deposits in the coronary arteries
2) This reduces the diameter of the artery
3) This increases the risk of a blockage - from the plaque itself or from a blood clot
4) A blockage limits the supply of oxygenated blood to the heart tissue
5) Not enough oxygen delivered to heart tissue
6) Reduced aerobic respiration which can lead to tissue death of heart muscle

Question 2

What is Angina?

Answer 2

Angina occurs when the narrowing of the coronary arteries restricts oxygen flow to the heart. This means heart tissue has to respire aerobically. It is thought that this leads to chemical changes and it is that the causes the heart pain

Question 3

What is the difference between a Stroke and a TIA

Answer 3

TIA affects a much smaller section of the brain and recovers much more quickly.

Question 4

How does a stroke occur?

Answer 4

Artery in the brain or leading to the brain is blocked by a clot or plaque

This reduces blood flow in the brain

Brain tissue is lacking in blood supply

Not enough glucose and oxygen supplied for respiration

Death of brin tissue leads to loss of function

Question 5

What is a TIA?

Answer 5

A ‘mini’ stroke where a smaller part of the brain is partially cut off from blood supply

Question 6

What is atherosclerosis and why is it bad?

Answer 6

The process that leads to CHD and Strokes (arterial blockages).

Fatty deposits blocking arteries increasing chances of thrombosis which decreases blood supply

Question 7

Which type of vessel does atherosclerosis occur in?

Answer 7

Arteries

Question 8

Describe the process of Atherosclerosis (including the positive feedback)

Answer 8

1. The endothelium becomes damaged and dysfunctional - sometimes caused by high blood pressure
2. This breach causes an inflammatory response - WBCs come to the artery wall near the damage. This causes cholesterol to accumulate. FATTY DEPOSIT ATHEROMA FORMS
3. Calcium salts and fibrous tissue also build up at the site. THIS CAUSES A HARD PLAQUE TO FORM (under the endothelium). Fibrous tissue causes the artery wall to lose elasticity and harden.
4. Plaque causes the lumen to narrow. This increases blood pressure. High blood pressure can lead to endothelial damage which can cause further plaque to build up. This causes a positive feedback loop.

Question 9

Describe the process of the clotting cascade

Answer 9

1. Platelets and damaged tissue release the protein THROMBOPLASTIN
2. Thromboplastin activates the PROTHOBIN (soluble in the blood) protein to be converted into the THROMBIN enzyme. vitamin K and Ca ions must be present
3. Thrombin catalyses the conversion of Soluble FIBRINOGEN into Insoluble FIBRIN
4. Fibrin forms fibres which tangle platelets and red blood cells together to form a blood clot

Platelets/Damged tissue&raquo_space; THROMBOPLASTIN

Thromboplastin- vitamin K and Ca ions must be present - PROTHROMBIN&raquo_space; THROMBIN

Thrombin - FIBRINOGEN&raquo_space; FIBRIN

FIBRIN + PLATELTS + RBCs = CLOT

Question 10

What releases thromboplastin?

Answer 10

Platelets and damaged tissue

Question 11

What reaction does thromboplastin catalyse?

Answer 11

Prothrombin into Thrombin

Question 12

What type of substance is prothrombin?

Answer 12

protein

Question 13

What type of substance is thrombin?

Answer 13

Enzyme

Question 14

Name 2 clotting factors that have to be present to make Thrombin

Answer 14

Calcium ions and Vitamin K

Question 15

What does thrombin enzyme do?

Answer 15

Catalyse the reaction of Fibrinogen into Fibrin

Question 16

Is Fibrinogen soluble?

Answer 16

Yes

Question 17

Is Fibrin soluble?

Answer 17

No