Veins
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Veins are thin walled structures compared to arteries that carry impure blood to the heart.
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The structure of veins resembles the arteries with few differences.
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The venous wall is composed of all the three layers but much thinner due to the reduction of muscular and elastic tissue components and lack of limiting membrane.
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The veins collapse when empty due the fact that they are thinner.
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Most of the veins excepting the trunk veins are provided with valves. These valves are formed by in folding of the tunica intima.
Blood supply and innervation
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The walls of the arteries and veins are supplied with blood by a large number of small arteries termed vasa vasorum.
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The lymphatics also ramify chiefly in the external coat.
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The nerves accompany the vessels, forming plexus around them and terminate in the muscular layer of the middle coat.
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Last modified: Sunday, 16 October 2011, 11:01 AM