lymphatic system

• Lymphatic System


  A one-way system of dead-ended vessels
• Components of the Lymphatic System

  • Lymph Vessels
  • Lymph Fluid
  • Lymph Nodes

  
• Lymph Vessels


  • Dead-ending vessels
  • Have valves which prevent the backflow of lymph
  • Found throughout the body
  • Collect tissue fluid that surrounds the cells and return it back to the blood at the subclavian vein

  
• Lymph Fluid


  A colourless fluid formed from tissue fluid, with a composition very similar to plasma but with less proteins
• Lymph Nodes


  • Swellings found along the lymph vessels
  • Contain large numbers of lymphocytes
  • Form clusters called glands in some parts (thymus, tonsils, spleen, adenoids, armpits, neck)

  
• Blood in capillaries is under high pressure


  Plasma and dissolved substances leave the blood at the arterial end to form tissue fluid or extra cellular fluid (ECF)

  
• Tissue fluid bathes the cells

  Delivers oxygen and glucose to cells and collects carbon dioxide
• Most of the tissue fluid

  Drains back into the blood stream at the venous end of the capillary

  
• Some of the tissue fluid

  Enters the lymphatic system, becoming lymph

  
• Functions of the Lymphatic System

  • Transports lymph back to the bloodstream via the subclavian vein
  • Absorption and transport of fat through the lacteals in the villi of the small intestine
  • Defence (filters out bacteria and other pathogens, produces lymphocytes that fight infection)