Circulatory system Flashcards
closed circulatory system
blood stays in blood vessels
all vertebrates fish mammals
why single circulation
low activity and fo not need to maintain temperature so less energy needed
advantages of double
blood flows quickly due to blood pressure rested by heart
hear can increase pressure of blood flowing to body without increasing it for the lungs
1mm
1000 micrometer
explain why a mammal born with a hole between the 2 ventricles will have shortness of breath
less oxygen available for aerobic respiration
deoxygenated and oxygenated blood mix
therefore reducing concentration of oxygen in the blood circulating in the body
because some deoxygenated blood does not go to the lungs
order of cardiac cycle
atrial systole - ventricular systole - cardiac diastole
what happens in atrial systole
As atria fills with blood, pressure increases in atria. This causes AV valves to be forced open.
Blood from atria flows into relaxing ventricles.
Atria contracts to force remaining blood into the ventricles so there is a slight increase in ventricular pressure.
what happens in ventricular systole
Ventricles contract causing the ventricular pressure increases so the AV valves close.
This increase in ventricular pressure forces semilunar valves to open, so blood is forced into the aorta and pulmonary artery.
Aortic (or pulmonary artery) pressure increases as a result of large volume of blood from the ventricles entering the arteries at a high pressure.
what happens in cardiac diastole
Both the atria and ventricles are relaxed so the pressure is low. The pressure in the ventricles drops below that in the aorta and pulmonary artery, causing semilunar valves to close.
Pressure in the atria rises above that in the ventricles so atrioventricular valves open. Blood flows into atria.
blood vessel with no collagen
capillary
benefits of plant statins to human health
lower blood cholesterol
inhibition of cholesterol synthesis in liver
reduces risk of CVD
one risk associated with anticoagulants
internal bleeding
how do anticoagulants reduce the risk of cvd
prevent formation of blood clots
reduces ‘stickiness’ of platelets
clotting factors not inhibited
risk of blood vessels being blocked is reduced
function of semilunar valves in aorta
opens as blood pumps into aorta
valves close during diastole
prevents backflow of blood into ventricle
vena cava
carries deoxygenated blood from body into right atrium
