heart, red & white blood cells, arteries and veins

1. STRUCTURESAND
FUNCTIONSOFTHE
CIRCULATORYSYSTEM

2. Heart
The heart is the main organ in the circulatory system and without it we
would die its main purpose is to circulate blood around the body.
The heart works like this:
1. de-oxygenated blood gets in the right atrium into the Vena Cava.
2. The blood passes through a valve in the right ventricle.
3. From there travels up to the lungs into the pulmonary artery.
4. The blood gets oxygenated in the lungs and comes back down
to the left atrium, through the pulmonary vein.
5. From the left atrium it goes through another valve in the left ventricle.
6. Last the blood is pumped throughout the body through the aorta.

3. redbloodcells
Red blood cells are one of the key things in the
circulatory system. They get produced in the bone
marrow and are transported for 120 days until they
are destroyed in the spleen. When these get destroyed the iron inside of them is
preserved and stored in the liver.
Spleen- acts as a filter for blood in the immune system, recycles red blood cells, stores
platelets and white blood cells. The spleen also fights bacterias.
Liver- his main job is to filter the blood that comes from the digestive tract and
detoxifies chemicals and metabolizes drugs before pumping it to the body.

4. whitebloodcells
White blood cells are also one of the keys in
the circulatory system. Like the red blood
cells are produced in the bone marrow. The
function of these ones is to fight with micro-
organisms and they also help strengthen the
immune system. They are involved in
protecting the body against infectious
disease and foreign invaders. All blood cells
have nuclei that distinguish them from the
red blood cells and the platelets.

5. arteries
Arteries are elastic tubes that carry blood
away from the heart. When arteries move
away from the heart they divide in small
vessels. The biggest arteries are as big as
a thumb and the smallest arteries are
thinner than a hair these thinner arteries
are called arterioles. Arteries carry bright
red blood and the color comes from the
oxygen it carries.

6. veins
Veins carry the blood to the heart. The
smallest veins are called venules and are very
thin. They join larger veins that open in the
heart. The veins carry dark red blood that
doesn't have much oxygen. Veins have thin
walls. They are not as strong as the arteries
because as blood is returned to the heart, it is
under less pressure.