COMPONENTS OF
CIRCULATORY SYSTEM
LO
 Recall the three main types of blood
vessel.
 Describe the function of blood vessels
 Link the structure of blood vessels to their
function.
What are the main components of our circulatory system
and their function?
What is the Function of
the circulatory system?
What are the main
components?
Heart
Arteries
Arteries
Veins
Capillaries
Carry blood away from the
heart; divide to form smaller
arterioles
Carry blood towards the heart;
small veins are called venules
Link arterioles and venules
together and are small,
microscopic vessels.
Arterioles
Capillaries
Venules
Veins
Arteries
Blood in arteries travels away
from the heart, and towards
organs.
It travels at high pressure and is
usually oxygenated.
The artery has thick muscular
walls to withstand the high
pressure.
VEINS
Veins take blood to the heart
and away from organs.
Blood travels at low pressure
so veins have valves to
prevent blood going
backwards.
The blood inside veins is
usually deoxygenated.
CAPILLARIES
Capillaries are microscopic
vessels that connect arterioles
to venules.
They are only 1 cell thick and
allow substances to be
exchanged between blood and
body cells.
ARTERIES
Carry blood away from the
heart.
Return blood to the heart
Have thicker walls.
Blood moves more slowly
due to lower pressure.
Have valves.
Blood is bright red.
Blood contains less O2.
VEINS