Transcript Blood Vessels

Blood Vessels
ACCESS HE
Human Biology.
Clare Hargreaves-Norris
Introduction
Blood vessels are tubular in shape and
their function is to form a network to
transport the blood around the body,
Clare Hargreaves-Norris
Circulatory System (General).
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Blood Vessels (Three Types).
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Arteries.
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Veins.
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Capillaries.
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Structural differences between
Arteries and Veins.
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Arteries:
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Carry blood away from the heart to the rest of the body.
Carry oxygenated blood except the pulmonary artery.
Blood travels at a higher pressure.
Arteries have a small lumen.
Arteries eventually form into smaller vessels called
arterioles.
Contain no valves.
Tend to lie deeper in the body.
Have thicker muscular walls.
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Veins:
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Carry blood to the heart from the body
Carry deoxygenated blood except the pulmonary vein
Blood travels at a lower pressure
Veins have a large floppy lumen.
The veins eventually form into smaller vessels called venules
Veins are situated in between muscles & contain valves to
prevent the blood flowing backwards
Lie more superficially in the body
Have thinner muscular walls
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Capillaries:
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Narrow blood vessels which have very thin walls,
just one cell thick
Substances can pass through its walls
Exchange oxygen and nutrients for carbon
dioxide and wastes within all cells and tissues
Forms the link between arterioles and venules
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Arteries, Veins and Capillaries.
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Journey of the blood
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When ventricles of the heart contract, oxygenated blood
is forced out of the heart from the left side, and on its
journey around the body in vessels called arteries.
The oxygenated blood travels at a faster pace and under
higher pressure due to the force of the heart pumping it
around the body.
Eventually the blood will pass into smaller vessels called
arterioles.
The arterioles eventually form into even smaller vessels
called capillaries.
Because capillaries are so small, they form an intricate
network around all of the tissues and cells within the
body.
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Journey of the Blood (Cont).
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The capillary walls are only one cell thick and allow certain
substances to pass out through the capillary walls to
bathe the cells with vital oxygen and nutrients.
Waste products and carbon dioxide are produced by the
cells and these pass back into the capillaries via a similar
process.
The capillaries take away the waste products and carbon
dioxide and eventually form into larger vessels called
venules.
The venules eventually form into larger vessels called
veins.
Veins carry the deoxygenated blood back to the heart
under lower pressure, as the blood starts to slow down
after its long journey around the body.
Clare Hargreaves-Norris
Journey of the Blood (Cont).
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To assist the return of the deoxygenated blood the veins
are located in-between muscles. When the muscles
contract they squeeze the veins forcing the blood upwards
and onwards.
Valves are also located within the veins to prevent the
blood from flowing backwards.
On its journey, any waste products are filtered from the
blood and removed from the body via the urinary and
excretory systems.
Eventually the blood returns back to the heart
The blood is then pumped into the lungs to be replenished
with oxygen and have the carbon dioxide removed.
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Arteries of the head
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Arteries of the
body
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Oxygenated blood is
transported to all cells and
tissues of the body via the
arteries.
The aorta is the main artery
that leaves the heart.
This then branches off to
form further arteries.
Arteries become smaller to
supply all areas of the body.
Small arteries are called
arterioles.
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Veins of the head
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Veins of the
body
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Deoxygenated blood is
transported from all cells
and tissues in the body
back to the heart.
Small veins are called
venules.
Venules become veins.
The largest veins are the
superior and inferior vena
cava.
The superior and inferior
vena cava returns the
deoxygenated blood back
to the heart.
Clare Hargreaves-Norris