exchange and transport (the heart)

Question 1

what type of blood does the right hand side of the heart pump?

Answer 1

deoxygenated blood to the lungs

Question 2

what type of blood does the left hand side of the heart pump?

Answer 2

oxygenated blood to the whole body

Question 3

why is the left ventricle of the heart thicker?

Answer 3

needs to contract to pump blood all around the body, not just to the lungs

Question 4

why do ventricles have thicker walls than atria?

Answer 4

need to push blood out of the heart not just around the heart

Question 5

what do the atrioventricular valves do?

Answer 5

link the atria to the ventricles and stop blood flowing back into the atria when the ventricles contract

Question 6

what do the semi lunar valves do?

Answer 6

link the ventricles to the pulmonary artery and aorta, and stop blood flowing back into the atria when the ventricles contract

Question 7

when do valves open?

Answer 7

when there is higher pressure behind a valve

Question 8

when do valves close?

Answer 8

when the pressure in front of the valve is higher

Question 9

what are the stages of the cardiac cycle?

Answer 9

ventricles relax
atria contract
increase in pressure pushes blood into ventricles
atria relax
ventricles contract
increase in pressure in ventricles forces atrioventricular valves shut to prevent backflow
pressure in ventricles higher than aorta and pulmonary artery- forces open semilunar valves
blood forced out
ventricles and atria both relax
pressure higher in pulmonary artery and aorta- closes semilunar valves to prevent backflow
blood returns to heart
atria refill
increases pressure of atria

Question 10

what happens in diastole?

Answer 10

atria and ventricles relax
blood enters atria via vena cava and pulmonary vein
increase in pressure in the atria

Question 11

what happens in atrial systole?

Answer 11

atria contract- increases pressure
atrioventricular valves open
blood flows into ventricles
ventricles relax

Question 12

what happens in ventricular systole?

Answer 12

ventricles contract 
pressure higher in the atria 
atrioventricular valves close 
semi lunar valves open
blood pushed into pulmonary artery

Question 13

how are atheromas formed?

Answer 13

if endothelium is damaged, white blood cells and lipids clump under the lining to form fatty streaks
over time, build up and harden= fibrous plaque-atheroma
partially blocks the lumen of the artery
restricts blood flow- causes blood pressure to increase

Question 14

what is coronary heart disease?

Answer 14

coronary arteries have lots of atheromas
restricts blood flow to the heart muscle
can lead to myocardial infraction

Question 15

what is an aneurysm?

Answer 15

atheromas damage and weaken arteries
narrow arteries which increases blood pressure
blood travels through weakened artery at high pressure-pushes inner layers of artery through elastic layer
=balloon like swelling
may burst= haemorrhage

Question 16

what is thrombosis?

Answer 16

atheroma can rupture the endothelium
damages the artery wall=rough surface
platelets and fibrin accumulate at the site of damage= blood clot
can block the artery

Question 17

what is a myocardial infarction?

Answer 17

if a coronary artery becomes blocked- an area of the heart muscle will be cut off from its blood supply and receive no oxygen
causes a myocardial infarction (heart attack)

Question 18

why is high blood cholesterol/poor diet a risk factor for cardiovascular disease?

Answer 18

cholesterol makes up fatty deposits which form atheromas- which can lead to increased blood pressure and clots
diet high in saturated fat/salt= risk

Question 19

why is cigarette smoking a risk factor for cardiovascular disease?

Answer 19

nicotine increases the risk of blood pressure
carbon dioxide combines with haemoglobin and reduces the amount of oxygen transported in the blood
smoking decreases amount of antioxidants in blood which protect cells from damage

Question 20

why is high blood pressure a risk factor for cardiovascular disease?

Answer 20

increases the risk of damage to artery walls
damaged walls have an increased risk of atheroma formation
can cause blood clots