Blood Vessels
Arteries carry blood from the heart out to
the capillaries. Their walls are fairly thick and contain elastic
fibers and/or smooth muscle fibers.
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Artery and Vein (High Power) |
Capillaries are the tiniest of the blood vessels.
They consist of a single layer of simple squamous epithelium rolled
into a tube. Their thin walls allow nutrients, oxygen, etc. to freely
move out of the blood to reach the cells.
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Capillary (microscopic)
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Veins return blood from the capillary beds to the
heart. Many veins contain valves which, aided by surrounding muscular
movements, help keep the blood moving toward the heart.
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Vein and Artery (microscopic)
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