6. ;kajno;nd
Humans have a
closed circulatory
system.
This means blood
circulates around
the body without
ever leaving the
blood vessels.
Artery Vein
Arteriole Venule
Capillary network
7. Capillaries: Many small, narrow tubes.
Walls are very thin – cells come into close contact with the blood.
Capillaries supply cells with O2 and nutrients, and removes waste
products and CO2.
Capillaries combine again to form veins.
Veins: Transport deoxygenated blood back to lungs via the heart.
Thinner, less muscled walls.
The pulmonary vein transports oxygen-rich blood from the lungs to the
heart. It is the only vein that transports oxygen-rich blood.
Arteries: Transport oxygen-rich blood from the heart to the cells of
the body.
Walls are thick, muscled and elastic - The aorta is the main artery.
The pulmonary artery transports deoxygenated blood from the heart to
the lungs. It is the only artery that transports deoxygenated blood.
8.
9. Functionsof
Pumps deoxygenated blood to the lungs where
it gets rid of CO2.
Blood enriched with O2 flows back to the heart
from the lungs.
From where it is pumped to the rest of the body.
In this way the rest of the body is supplied with
O2.
The heart is centrally situated in the chest between the lungs.
It is protected by the chest and ribs.
Your heart is approx. the size of your fist.
The two sides of the heart are separated by a muscular wall (septum).
Both sides are also divided into two chambers. The human heart therefore consists of four chambers.
The upper two heart chambers (atria) receive blood from the veins.
The lower two chambers (ventricles) pump blood to the rest of the body through the arteries.
The heart is actually a hollow muscle that alternately contracts and relaxes continuously.