circulatory system - blood vessels Flashcards
what do arteries do
carry blood away from the heart
why are arteries useful
they carry blood under pressure
why are arterie walls strong and elastic
because the blood they have to carry is high pressure
what makes arteries strong
they have thick layers of muscle
why are arteries elastic
to allow them to stretch and spring back
what’s the hole down the middle of an arterie
lumen
what do arteries branch into
capillaries
describe what capillaries look like
too small to see
one cell thick
thin wall
small lumen
what do capillaries do
carry blood really close to every cell to exchange substances with them
why do capillaries have gaps in them
so substances can diffuse in and out
what do capillaries supply
food and oxygen and take away waste like carbon dioxide
why are capillaries only one cell thick
so diffusion is very fast
capillaries join up to form ….
veins
what do veins do
take blood back to the heart
what pressure blood does veins carry
low
