Veins

VEINS

  • Veins are thin walled structures compared to arteries that carry impure blood to the heart.
  • The structure of veins resembles the arteries with few differences.
  • 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.
  • The veins collapse when empty due the fact that they are thinner.
  •  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

  • The walls of the arteries and veins are supplied with blood by a large number of small arteries termed vasa vasorum.
  • The lymphatics also ramify chiefly in the external coat.
  • The nerves accompany the vessels, forming plexus around them and terminate in the muscular layer of the middle coat.
Last modified: Sunday, 16 October 2011, 11:01 AM