Lymphatic system (2) (1) (1)

• What are lymph vessels similar to?

  Small veins
• What are the three layers of lymph vessels?

  Outer fibrous layer, smooth muscle, elastic tissue
• What keeps lymph flow heading towards the thorax?

  Cup-shaped valves in lymph vessels
• What determines the movement of lymph?

  Skeletal muscle movement and lymphatic pump
• What are the two large ducts formed by lymph vessels?

  Thoracic duct and Right Lymphatic Duct
• How long is the thoracic duct?

  40 cm long
• Where does the thoracic duct open?

  Left subclavian vein
• What does the thoracic duct drain lymph from?

  Legs, pelvic and abdominal cavities, left side
• How long is the Right Lymphatic Duct?

  1 cm long
• Where does the Right Lymphatic Duct open?

  Right subclavian vein
• What does the Right Lymphatic Duct drain lymph from?

  Right half of thorax, head, neck, right arm
• How many lymph nodes are in the body?

  600+
• What is the size range of lymph nodes?

  Pin-head to small almond
• How does lymph drain through lymph nodes?

  Through a number of nodes, usually 8 to 10
• What forms the outer fibrous capsule of lymph nodes?

  Fibrous tissue
• What do trabeculae in lymph nodes do?

  Dip into the body to support structure
• What does the body of the lymph node consist of?

  Reticular fibers and lymphatic tissue
• What immune cells are contained in lymphatic tissue?

  Phagocytes, B-lymphocytes, T-lymphocytes
• What do dendritic cells do in lymph nodes?

  Act as antigen presenting cells
• What do B-cells differentiate into?

  Plasma cells that create antibodies
• What do circulating helper T-cells do?

  Activate the adaptive immune response
• What do macrophages and neutrophils do?

  Phagocytose antigens
• What is the role of antibodies in phagocytosis?

  Coat pathogens to increase uptake by phagocytes
• How do antibodies activate the complement system?

  Bind to pathogens and stimulate phagocytic cells
• What does the lymphatic system consist of?

  • Lymph
  • Lymph vessels
  • Lymph nodes
  • Lymph organs (Spleen, Thymus)
  • Diffuse lymphoid tissue (Tonsils)
  • Bone marrow
• What occurs in the thymus gland?

  Maturation of lymphocytes from red bone marrow
• What do T-lymphocytes do after maturing in the thymus?

  Leave the thymus and enter the bloodstream
• What happens to the thymus gland after puberty?

  Atrophies from 70g to 3g
• Where is the spleen located?

  Between the stomach and diaphragm
• What is the largest lymph organ?

  Spleen
• What does the spleen control?

  Levels of white blood cells, red blood cells, platelets
• What are the two types of pulp in the spleen?

  Red pulp and white pulp
• What does red pulp in the spleen do?

  Filters blood of antigens and worn-out cells
• What does white pulp in the spleen contain?

  Areas of lymphoid tissue with T and B cells
• What is the hilum of the spleen?

  Area with artery, vein, efferent lymph vessel, nerves
• What is one function of the spleen?

  Phagocytosis of erythrocytes and cellular material
• What is another function of the spleen?

  Blood storage as a reservoir
• What can cause splenomegaly?

  Lymphocyte proliferation due to antigens
• What is erythropoiesis?

  Production of blood cells in the spleen and liver
• What is Mucosa Associated Lymphoid Tissue (MALT)?

  • Not encapsulated
  • Contains B- and T-lymphocytes
  • No afferent lymphatic vessels
  • Found in respiratory, gastrointestinal, and genitourinary tracts
  • Includes tonsils and Peyer's patches