Topic 1 - Cardiovascular Disease & Risks Flashcards
What is fibrinogen?
It is a soluble plasma protein that is converted into the insoluble protein, fibrin, which forms a mesh to trap blood cells to create a clot.
What happens when blood comes into contact with collagen due to a damaged artery wall?
It triggers a cascade of chemical changes.
Which enzyme is prothrombin converted into to convert fibrinogen into fibrin?
Thrombin.
Name the factors which can increase the risk of CVD?
High blood pressure, High cholesterol levels, Lack of exercise, Smoking, Stress.
Why does high blood pressure increase the risk of CVD?
Higher blood pressure means that artery walls can be damaged. This can lead to blood clots and atheromas, which can also increase blood pressure further in a positive feedback response. High blood pressure can also cause the heart muscles to strain, weakening them.
Why do high levels of cholesterol increase the risk of CVD?
High levels of cholesterol in a diet increases the production of LDLs, which causes the membrane receptors on cell membranes to become de-sensitised. This means that LDLs cannot be taken up be cells, leaving it in the bloodstream. This causes the cholesterol to be deposited in artery walls increasing blood pressure, and risk of atheromas.
Why does smoking increase the risk of CVD?
The haemoglobin in red blood cells carries carbon monoxide instead of oxygen, meaning the heart has to work harder to get more oxygen. Nicotine causes adrenaline to be produced, causing arteries and arterioles to constrict, increasing blood pressure. It is also linked with the reduction of HDL levels.
Name the properties of arteries.
Narrow lumen, thick walls, no valves, more collagen, elastic fibres and smooth muscle.
Name the properties of veins.
Wide lumen, thin walls, valves, less collagen, elastic fibres and smooth muscle.
What are the names for heart contraction and relaxation?
Systole (contraction) and diastole (relaxation).
Summarise what happens during atrial systole.
As blood flows into the atria, the pressure of the blood against the atrioventricular valves pushes them open. Then, the atria walls contract, forcing the blood into the ventricles.
Summarise what happens during ventricular systole.
As blood flows into the ventricles, they contract from the base upwards, forcing blood out of the heart through the arteries.
Summarise diastole.
The atria and ventricles relax , lowering pressure. This causes blood to flow into the atria from the veins.
Define atherosclerosis.
The disease process which leads to CHD and strokes. It is when fatty deposits either block an artery completely, or partially blocking it, increasing the chance of it being fully blocked by a blood clot.
Define the term hypertensive.
High blood pressure.
