Lymphatics

• What is the lymphatic system responsible for?

  Defending the body from hazards
• What does the immune system include?

  Cells and tissues involved in immunity
• What is immunity?

  The ability to resist infection and disease
• What are pathogens?

  Organisms that cause disease
• What is lymph?

  Fluid similar to plasma without proteins
• What do lymphatic vessels do?

  Carry lymph to veins
• What are lymphoid cells?

  Lymphocytes, phagocytes, and other cells
• What are lymphoid tissues dominated by?

  Lymphocytes
• What are primary lymphoid tissues and organs?

  Sites where lymphocytes are formed and mature
• Which organs are considered primary lymphoid organs?

  Red bone marrow and thymus
• What are secondary lymphoid tissues and organs?

  Sites where lymphocytes are activated
• Which organs are considered secondary lymphoid organs?

  Tonsils, MALT, lymph nodes, and spleen
• What are the functions of the lymphatic system?

  Produce, maintain, and distribute lymphocytes
• How does the lymphatic system regulate interstitial fluid composition?

  By transporting hormones, nutrients, and wastes
• What are meningeal lymphatics?

  Vessels that drain CSF to cervical lymph nodes
• What are lymphatic capillaries?

  Smallest lymphatic vessels in the body
• How do lymphatic capillaries differ from blood capillaries?

  They are closed at one end
• What is the function of the overlap of endothelial cells in lymphatic capillaries?

  Acts as a one-way valve for fluid entry
• What is lymphedema?

  Obstruction of lymphatic vessels causing swelling
• What are superficial lymphatics?

  Vessels in the subcutaneous layer
• What do deep lymphatics accompany?

  Arteries and veins
• What do the thoracic duct and right lymphatic duct do?

  Collect lymph from different body regions
• Where does the thoracic duct empty?

  Into the left subclavian vein
• Where does the right lymphatic duct empty?

  Into the right subclavian vein
• What are lymphoid cells?

  Immune system cells in lymphoid tissues
• What are the types of lymphocytes?

  T cells, B cells, and NK cells
• What are lymphoid nodules?

  Areal tissue densely packed with lymphocytes
• Where are lymphoid nodules found?

  Along the digestive, urinary, and reproductive tracts
• What is the germinal center?

  Central zone of the nodule with dividing lymphocytes
• What are tonsils?

  Large lymphoid nodules in the pharynx
• What is tonsillitis?

  Inflammation of the tonsils
• What is mucosa-associated lymphoid tissue (MALT)?

  Lymphoid tissues associated with mucosa
• What are Peyer's patches?

  Clusters of lymphoid nodules in the intestine
• What is the appendix?

  Tube-shaped sac with lymphoid nodules
• What separates lymphoid organs from surrounding tissues?

  A connective tissue capsule
• What are the major lymphoid organs?

  Lymph nodes, thymus, and spleen
• What is the structure of lymph nodes?

  Surrounded by a capsule with trabeculae
• What is the hilum of a lymph node?

  Indentation where vessels and nerves enter
• How does lymph flow through lymph nodes?

  From afferent lymphatics to efferent lymphatics
• What happens in the cortex of lymph nodes?

  Contains B cells within germinal centers