Topic 1 Quiz Flashcards

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Why do many organisms have a heart and circulation system?
To overcome the limitations of diffusion by using mass transport, to better meet the needs of the organism.
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List reasons why many animals have a heart and circulation system.
To move substances by mass flow faster than is possible using diffusion. To allow the transport of substances from exchange surfaces with large surface area to the rest of the body. Because a beating heart moves blood through the body faster.
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What is an open circulatory system?
The open circulatory system pumps blood into cavities surronding the animal's organs, allowing diffusion between the blood and the cells.
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What is a closed circulatory system?
A closed circulatory system has blood enclosed in tubes that supply all parts of the body.
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What is the advantage of a closed circulatory system over an open one?
The blood travels faster as the blood system is more effective at delivering substances around the body.
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What is the differene between a single circulation system and a double circulation system?
In a single, the blood passes through the heart once for each complete circuit. In a double circulation system, the blood passes through the heart twice for each complete circuit.
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Why is this advantageous to an organism?
It takes less time for the blood to do a complete circuit of the body, allowing for a higher metabolic rate due to the more rapid delivery of substances to cells.
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Why is water an effective transport molecule?
It is small, so is able to pass through cell membranes more effectively. It is bipolar (negative oxygen, positive hydrogen) so can bond with other substances when they dissolve in it.
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What is a capillary?
A fine branching blood vessel that forms part of a network between the arterioles and venules. The narrowest of the blood vessels in the body.
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Describe the structure of a capillary.
A tiny blood vessel with a narrow lumen and a wall/endothelium only one. cell thick.
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What is the role of capillaries?
To transport blood through the body. Due to their size, they are able to be close to a large number of cells in tissues without disturbing the structure, and their narrow endothelium allows for a high rate of diffusion and a short diffusion pathway.
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Other cards in this set

Card 2

Front

List reasons why many animals have a heart and circulation system.

Back

To move substances by mass flow faster than is possible using diffusion. To allow the transport of substances from exchange surfaces with large surface area to the rest of the body. Because a beating heart moves blood through the body faster.

Card 3

Front

What is an open circulatory system?

Back

Preview of the front of card 3

Card 4

Front

What is a closed circulatory system?

Back

Preview of the front of card 4

Card 5

Front

What is the advantage of a closed circulatory system over an open one?

Back

Preview of the front of card 5
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