Transcript Different circulatory systems

UNIT
2
The nutrition function
DIFFERENT
CIRCULATORY SYSTEMS
Natural Science 2. Secondary Education
UNIT
2
Different circulatory systems
CIRCULATORY
SYSTEMS
two types
OPEN
CLOSED
can be
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Natural Science 2. Secondary Education
SINGLE
DOUBLE
UNIT
2
Different circulatory systems
Circulatory systems
• They are present in most animals and consist of:
• A circulating liquid, like blood, that transports substances
throughout the organism.
• Vessels, which the liquid travels through.
• A pumping mechanism, the heart, which moves the liquid.
Heart
An example of a
closed circulatory
system, that of a
mammal.
Natural Science 2. Secondary Education
Blood vessels:
Arteries
Veins
Capillaries
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UNIT
2
Different circulatory systems
Animals with open circulatory systems
• Found in arthropods and molluscs.
• The circulating liquid leaves the vessels to bathe the organism’s
tissues with oxygen and nutrients. Once substances have been
exchanged with the tissues, the liquid is drawn back to the vessels.
The circulating
liquid is transported
through the vessels
to the tissues, where
substances are
exchanged.
A hole-filled heart
pumps the circulating
liquid.
The open
circulatory system
of an arthropod
Natural Science 2. Secondary Education
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UNIT
2
Different circulatory systems
Animals with closed circulatory systems
• Found in vertebrates and some invertebrates, such as annelids.
• The circulating liquid is only found inside the vessels.
The exchange of substances takes place through the walls of the
smallest vessels, called capillaries.
• There are two types:
• Single
The circulating
liquid stays inside
• Double
the vessels.
Substances are
interchanged in
the capillaries.
A heart with no
holes pumps the
circulating liquid.
The closed circulatory
system of a fish
Natural Science 2. Secondary Education
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UNIT
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Different circulatory systems
Animals with single closed circulatory systems
• Found in some invertebrates and in fish.
• The heart pumps the circulating liquid, which travels to the
respiratory organs, where it absobs oxygen. From there it
travels throughout the rest of the body.
• After interchanging substances with the body, the blood goes
back to the heart.
3: The blood travels
throughout the body
interchanging
substances.
4: The blood
travels from the
different organs
back to the heart.
2: The blood goes to
the gills, where
oxygen is absorbed.
1: The heart pumps
the blood.
The single closed circulatory
system of a fish
Natural Science 2. Secondary Education
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UNIT
2
Different circulatory systems
Animals with double closed circulatory systems
• Found in land vertebrates.
• The heart pumps the blood to the lungs in pulmonary circulation.
The blood releases carbon dioxide and absorb oxygen.
• The blood then returns to the heart, where it is pumped to the
organs. Substances are interchanged in the organs.
• The blood then travels from the different organs back
to the heart.
1: The heart pumps
the blood.
The double closed
circulatory sytem
of a bird
Natural Science 2. Secondary Education
2: The blood travels to
the lungs, where it
absorbs oxygen, and
returns to the heart.
3: The heart pumps
the blood again,
which flows to
different organs.
4: The blood
travels from the
different organs
back to the heart.
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