SPEC POINT 1.6

Question 1

Describe the events leading to the formation of blood clots:

Answer 1

1. Damage to artery endothelium exposes collagen fibres
2. Platelets are activated, forming a platelet plug and releases the protein thromboplastin
3. Calcium ions from plasma and thromboplastin trigger conversion of soluble prothrombin protein into enzyme thrombin. Thrombin catalyses conversion of soluble protein fibrinogen to insoluble protein fibrin.
4. Fibrin polymerises to form mesh, trapping more platelets and RBC’s - a blood clot is formed
5. positive feedback
6. Until exposed collagen fibres are covered, which ends the response
7. Too much clotting (due to CVD risk factors) can result in blood clots that block arteries which reduces concentration gradients, rate of diffusion, respiration, ATP, cell death, etc.

Question 2

How can atherosclerosis or blood clotting result in a heart attack? (understanding that this is when heart tissue cells stop functioning)

Answer 2

1. Atherosclerosis or blood clots in coronary arteries restrict blood flow to areas of the heart.
2. This reduces oxygen supply and concentration gradients
3. The rate of diffusion of oxygen into cells is inadequate for respiration to occur so ATP levels drop and heart cells stop functioning
4. The heart fails to contract, causing a heart attack

Question 3

How can atherosclerosis or blood clotting
result in a stroke? (understanding that this is when brain tissue cells stop functioning)

Answer 3

1. Atherosclerosis or blood clots in brain arteries restrict blood flow to areas of the brain
2. This reduces oxygen supply and concentration gradients
3. The rate of diffusion of oxygen into cells is inadequate for respiration to occur so there is no aerobic respiration and no ATP produced. The brain needs lots of ATP to function, so lactic acid is produced from anaerobic respiration which inhibits enzymes and is toxic. Brain cells/neurons stop functioning
4. Significant loss of brain tissue function results in a stroke

Question 4

How can atheromas (a buildup of plaque in your arteries, resulting in narrow lumen) increase the risk of blood clotting?

Answer 4

The plaque deposit from atheromas can damage the endothelium, triggering thrombosis

Question 5

What is fibrinogen?

Answer 5

A soluble plasma protein

Question 6

What is cardiovascular disease?

Answer 6

What is cardiovascular disease?