the lymphatic system

• Lymph: clear liquid that is collected from around cells and is transported by the lymphatic system back to the bloodstream.
• Lymph vessels: narrow, dead-ending tubes that transport lymph and are present in every tissue and organ throughout the body.
• Lymph nodes: small, spherical-shaped organs of the lymphatic system that contain many white blood cells.
• Spleen: organ located just to the left of the stomach producing lymphocytes and filtering out bacteria, viruses and abnormal cells.
• Thymus: specialised lymphatic organ located just in front of the heart and underneath the sternum. It functions in the maturation of lymphocytes.
• Functions of the Lymphatic System

  • Collectinglosttissuefluid.

  • Returning lost fluid and protein to the blood

  – this helps maintains the blood at the right concentration.

  • Defence against pathogens

  – detects and filters out foreign antigens – lymphocyte and antibody production

  • Absorption and transport of fats

  – lacteals in the villi of the small intestine

  • Assists in hearing and balance – lymph is found in the inner ear
• What is the lymphatic system?


  A second circulatory system that is one way of dead ending vessels and lymph nodes
• What are lymph nodes?


  Swelling in the lymph vessel
• What is the function of lymph nodes?


  To fight infections in the body
• How is tissue fluid formed?

  High blood pressure in arteries forces small proteins and fluid out of blood plasma from arterioles
• What is tissue fluid also known as?

  Extracellular fluid (ECF)
• Where is extracellular fluid found?


  It surrounds all the cells in the body
• How does tissue fluid compare to blood plasma?


  Tissue fluid is the same as blood plasma minus the RBCs or platelets
• Why must extracellular fluid be removed?


  Because it is produced continuously
• What percentage of tissue fluid returns naturally to the capillaries?


  90%
• What happens to the remaining 10% of tissue fluid?


  It enters lymph vessels and is called lymph
• What does lymph contain?

  Lots of WBCs, proteins, and fats
• What is the role of lacteals in the lymphatic system?


  To transport glycerol and fatty acids to the lymph vessel
• What do lymph vessels eventually combine to form?


  The thoracic duct and right lymphatic duct
• What is the function of lymph nodes in the lymphatic system?


  To filter bacteria and harmful material from lymph and store WBCs
• What are the main functions of the lymphatic system?


  1. To collect tissue fluid and return it to the blood
  2. To defend the body against infection by filtration, storing lymphocytes, and destroying microorganisms
  3. To absorb and transport fats in the digestive system