Difference between veins and lymphatic vessels?

Answer 1

Comparison between Lymph Vessels and Veins.

• Similarities.
  • both have an interconnecting network of progressively larger vessels;
  • both transport fluids to the heart;
  • the larger lymph vessels have the same structure as veins, i.e. their walls have the same three layers;
  • both have semi-lunar valves to prevent any backward flow of blood;
  • the flow of fluid is slow but steady and at low pressure;
  • the fluid is deoxygenated;
  • like blood capillaries, the walls of lymph capillaries are composed of a single thin layer of squamous endothelium.
• Differences.
  • the walls of lymph vessels are musch thinner and more transparent;
  • the muscle layer in lymph vessel is much less developed, but there is more connective tissue;
  • blood capillaries form a continuous, open circuit, whereas lymph capillaries end blindly in the tissues;
  • lymph capillaries have a larger diameter than blood capillaries;
  • lymph capillaries have walls which are more permeable than the walls of blood capillaries. Consequently, larger molecules (such as proteins) are able to diffuse through them.

Answer 2

The Lymphatic collecting vessels have the same three tunics as veins, but the collecting vessels are thinner walled, have MORE internal valves than veins, and anastomose more.