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Investigation 6.6
Nutrient Exchange Between Body Cells and the Circulatory System |
We have attempted to construct a model for movement of nutrients from the intestines into the circulatory system. Now we need to consider how these nutrients get out of the capillaries and into cells all over your body, even as far away as your big toe. |
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Look back at the drawings you made of arteries and capillaries taking blood to the cells of the body. Do you remember how small the cells and capillaries are? Draw a picture in your lab book to show how capillaries appear next to a group of cells. |
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When the red blood cells move through the capillaries what is unusual about their arrangement? |
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How many can fit across one capillary? |
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How close are the capillaries to individual cells? |
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Why is it important that the blood in these vessels continues to circulate around the body? |
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In an earlier lesson you discovered that the circulatory system is a closed system. That is, the vessels move away from the heart, branch off into smaller and smaller vessels, then return to the heart as the tiny capillaries join into larger and larger veins all the while keeping the blood inside. |
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Why is it important that the blood in these vessels continues to circulate around the body? |
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What happens when the blood cells carrying oxygen and the nutrients dissolved in the blood reach the cells of the body? |
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Think about the size of blood cells and the size of other body cells. How does this affect your model? |
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Do the blood cells leave the capillaries? Discuss this with your group and see if you can come up with a convincing argument for why or why not? |
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