1003

• Body's Defenses


  • Barrier Defenses
  • Cellular Defenses
  • Inflammatory Response
  • Immune Response
• Barrier Defenses


  • Skin
  • Mucous Membranes
  • Gastric Acid
  • Major Histocompatibility Complex
• Skin


  • Protects the internal tissues and organs of the body
• Mucous Membranes


  • Line the areas of the body that are exposed to external influences, but do not have skin protection
• Gastric Acid


  Secreted by the stomach in response to many stimuli
• Major Histocompatibility Complex


  Distinguishes between self-cells and foreign cells
• Types of Cellular Defenses

  • Mononuclear Phagocyte System (MPS)
  • Thymus gland
  • Lymphatic tissue
  • Leukocytes
  • Lymphocytes
  • Numerous chemical mediators
• Lymphoid Tissues


  • Lymph Nodes
  • Spleen
  • Thymus gland
  • Bone Marrow
  • Lymphoid tissue throughout the respiratory and GI tracts
• Thymus gland


  A bipolar gland located in the middle of the chest, which becomes smaller with age
• A barrier defense that the body has is gastric acid
• Histamine Release


  • Locally Mediated Response
  • Vasodilation
  • Neutrophils
• Chemotaxis


  • Activated by arachidonic acid
  • Attract neutrophils
  • Aggressive
  • Local cellular breakdown and further inflammation
• Clinical Presentation


  • Heat
  • Swelling
  • Redness
  • Pain
• Chemotaxis assists in making macrophages and neutrophils very aggressive
• Types of T Cells

  • Effector or Cytotoxic T Cells
  • Helper T Cells
  • Suppressor T Cells
• Effector or Cytotoxic T Cells


  • Found throughout the body
  • Aggressive against non-self cells
  • Can directly destroy foreign cells or mark cells so other cells can destroy these cells
• Helper T Cells


  Stimulate the activity of B cells and effector T cells
• Suppressor T Cells


  • Monitor the chemical activity in the body
  • Act to suppress B-cell and T-cell activity when the foreign antigen is under control
• B Cell


  • Programmed to identify specific proteins or antigens
  • Involved in humoral immunity
  • Produce antibodies or immunoglobulins
• Other Mediators in the Immune Response

  • Interferons
  • Interleukins
  • Tumor Necrosis Factor (TNF)

  
• Interferons


  Prevent viral replication and suppress malignant cell replication and tumor growth
• Interleukins


  Chemicals secreted by active leukocytes to influence other leukocytes
• Tumor Necrosis Factor (TNF)


  Chemical released by macrophages; inhibits tumor growth and can cause tumor regression
• Immune and inflammatory responses


  Work together
• Pathophysiology Involving the Immune System

  • Neoplasms
  • Viral Invasion of Cells
  • Autoimmune Disease
  • Transplant Rejection