heart attacks

Question 1

heart attack

Answer 1

when the heart muscle is starved of blood ∴ cells cannot respire aerobically and die

Question 2

artery supplying heart muscle with blood

Answer 2

conorary artery

Question 3

other name for heart attack

Answer 3

myocardial infarction

Question 4

risk factors of heart attacks

Answer 4

• smoking
• high blood pressure
• high cholesterol
• diet

Question 5

how does smoking increase risk of heart attack? (3)

Answer 5

• CO reduces oxygen-carrying ability of haemoglobin as higher affinity, irreversibly binds ∴ to supply same amount of O2 to tissues, heart must work harder ∴ ↑ blood pressure
  
  • – also in exersise - O2 supply to heart tissues may be insufficient = heart attacks and pain
• nicotine stimulates production of adrenaline - ↑ heart rate + blood pressure ∴ ↑ risk heart attack
  - —- also makes platelets in blood more sticky - higher risk of thrombosis ∴ heart attack
• decreases amount of antioxidants in blood (important for protecting cells from damage ) fewer = more damage in coronary artery walls leading to atheroma formation

Question 6

how does high blood pressure increase risk of heart attack? (3)

Answer 6

• already higher pressure in arteries means that heart must work harder to pump blood ∴ more prone to failure
• higher pressure in arteries mean that they are more likely to develop aneurysms (weakening of wall) and burst = haemorrhage
• to resist high pressure within them, walls of arteries tend to be thickened and may harder, restricting blood flow

Question 7

how does high blood cholesterol increase risk of heart attack?

Answer 7

• (above 240mg per 100cm3)
• cholesterol is one of main constituents in fatty deposits that form artheromas
• artheromas lead to increased blood pressure and clots
• blocking flow of blood ro contrary arteries - cause heart attack
• high saturated fat diet associated w high blood cholesterol levels

Question 8

how does poor diet increase risk of heart attack

Answer 8

• high salt increases risk of high blood pressure

- high saturated fat is associated with High cholesterol levels

Question 9

atheroma formation

Answer 9

• several layers make up artery - inner layer = endothelium = usually smooth
• if damage occurs (eg. by high blood pressure) white blood cells clump together under lining to form fatty streaks
• over time more white blood cells, lipids and connective tissue build up and harden to form fibrous plaque = atheroma
• plaque partially blocks lumen of artery and restricts blood flow which causes pressure to increase

coronary heart disease occurs when coronary arteries have many atheroma which restricts blood flow = heart attack

Question 10

2 diseases affecting arteries:

Answer 10

aneurysm - (balloon like swelling of artery)

thrombosis (blood clot formation)

Question 11

process of aneurysm

Answer 11

• atheroma plaque damages and weakens artery - narrowing them increasing blood pressure
  
  • when blood travels through weakened artery ay high pressure it may push inner layers of artery through outer layer of elastic tissue to form swelling
  • may burst = haemorrhage (bleeding)

Question 12

process of thrombosis

Answer 12

• atheroma plaque can rupture the endothelia, of artery
• damages artery wall, leaving rough surface
• platelets and fibrin accumulate at damage site and form blood clot
• clot can cause complete blockage of artery to can become dislodged and block a vessel elsewhere in the body
• debris from rupture can case other clots to form further down artery