the heart and circulatory system Flashcards
what do arteries do
carry blood away from the heart
how is blood pumped out of the arteries
at high pressures
what are muscles in the arteries like
thick compared to the lumen, there are layers of muscle in the walls to make them strong
what allows the muscles in arteries to stretch and recoil
elastic fibres which helps withstand pressure created by pumping of blood
what do veins do
take blood back to the heart
what is blood like in the veins
at low pressure
what is the structure of the veins like
bigger lumen than arteries to help blood flow despite low pressures
what do capillaries join up to form
veins
what do arteries branch out into
capillaries
how are capillaries adapted to help exchange of substances
one cell thick to allow blood to flow really close to every cell in the body
why are capillaries narrow
to squeeze into gaps between cells
why do capillaries have a permeable wall
so substances can diffuse in and out
What is the role of the right atrium
receives deoxygenated blood through the vena cava from the body at LOW PRESSURE
where does the blood go after the right atrium
right ventricle
what does the right ventricle do
contracts to pump blood to the kings where it is oxygenated
where does blood go after the right ventricle
left atrium
what happens in the left atrium
receives oxygenated blood from the lungs through pulmonary vein still at low pressure
where does blood flow to after the left atrium
left ventricle
what happens in the left ventricle
oxygenated blood enters the left ventricle which contracts to pump it round the whole body via the aorta
why does the left ventricle have a much thicker wall
has to pump blood round the whole body at high pressure
what provides a strong heartbeat
muscular walls
what is the role of the septum
ensures that deoxygenated and oxygenated blood don’t mix
why does the heart have valves
stop back flow of blood so blood keeps flowing forward
what is cardiac output
volume of blood pumped out of the heart in a minute
