bsci202 exam 1 - lymphatic system

• functions of the lymphatic system:

  • return protein containing fluid from the interstitial fluid back to the blood
  • transport fat and fat soluble vitamins from GI tract to the blood
  • protect and defend body
  • macrophages and dendritic cells filter lymph
  • B and T lymphocytes provide immunity
• what is lymph?

  fluid that enters the lymph capillaries from the interstitium

  • similar in composition to blood plasma w/ less protein and more fat
• how is lymph circulated?

  lymphatic trunks merge until the lymph enters the 2 lymphatic ducts

  • right lymphatic duct drains lymph from upper right quadrant of the body
  • thoracic duct drains rest of lymph
• what are the lymphoid cells?

  lymphocytes, macrophages, dendritic cells, reticular cells
• what are reticular cells?

  connective tissue cells that produce reticular fibers for the stroma that supports other lymphoid cells in lymphoid tissues
• what is lymphoid tissue?

  made of reticular fibers (stroma) and lymphoid cells (macrophages, lymphocytes)
• what is diffuse lymphoid tissue?

  loose, uncapsulated tissue found in most organs and in MALT

  • forms pharyngeal, palantine, lingual tonsils
• what is MALT?

  mucous associated lymphatic tissue
• what are lymphoid follicles?

  like diffuse tissue but greater density of fibers

  • in lymph nodes, appendix, and peyer's patches
• what are the mechanisms used to circulate lymph?

  • contraction of skeletal muscles surrounding lymphatic capillaries, lymphatic's, lymphatic ducts
  • breathing creates pressure changes
  • presence of valves
  • pulsation of neighboring elastic arteries near lymph nodes
  • contraction of smooth muscles in walls of larger lymphatic vessels and lymphatic ducts
• what is the function of lymph nodes?

  filter substances traveling through lymphatic fluid and contain lymphocytes that help fight disease
• what is the function of the spleen?

  filters out old damaged cells and controls amount of blood and blood cells that circulate
• what is the function of the thymus gland?

  production and maturation of immune cells
• what is the function of tonsils?

  filters out germs entering your nose and mouth
• what is the function of peyer's patches?

  monitor germs that come into your body