exchange and transport (the heart) Flashcards
what type of blood does the right hand side of the heart pump?
deoxygenated blood to the lungs
what type of blood does the left hand side of the heart pump?
oxygenated blood to the whole body
why is the left ventricle of the heart thicker?
needs to contract to pump blood all around the body, not just to the lungs
why do ventricles have thicker walls than atria?
need to push blood out of the heart not just around the heart
what do the atrioventricular valves do?
link the atria to the ventricles and stop blood flowing back into the atria when the ventricles contract
what do the semi lunar valves do?
link the ventricles to the pulmonary artery and aorta, and stop blood flowing back into the atria when the ventricles contract
when do valves open?
when there is higher pressure behind a valve
when do valves close?
when the pressure in front of the valve is higher
what are the stages of the cardiac cycle?
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
what happens in diastole?
atria and ventricles relax
blood enters atria via vena cava and pulmonary vein
increase in pressure in the atria
what happens in atrial systole?
atria contract- increases pressure
atrioventricular valves open
blood flows into ventricles
ventricles relax
what happens in ventricular systole?
ventricles contract pressure higher in the atria atrioventricular valves close semi lunar valves open blood pushed into pulmonary artery
how are atheromas formed?
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
what is coronary heart disease?
coronary arteries have lots of atheromas
restricts blood flow to the heart muscle
can lead to myocardial infraction
what is an aneurysm?
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
what is thrombosis?
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
what is a myocardial infarction?
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)
why is high blood cholesterol/poor diet a risk factor for cardiovascular disease?
cholesterol makes up fatty deposits which form atheromas- which can lead to increased blood pressure and clots
diet high in saturated fat/salt= risk
why is cigarette smoking a risk factor for cardiovascular disease?
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
why is high blood pressure a risk factor for cardiovascular disease?
increases the risk of damage to artery walls
damaged walls have an increased risk of atheroma formation
can cause blood clots
