طفيليات مهمة

• Immunity


  The ability of the body to defend itself against specific foreign invaders (molecules or cells) obtained by having an infection or by vaccination
• Immunology


  The science that studies the structure and function of the immune system as well as the ways in which the body protects itself from diseases and infections

  
• Components of Immune system

  • Bone marrow
  • Thymus
• Bone marrow


  • Extremely important to the immune system because all the body's blood cells RBCs, WBCs (including T and B lymphocytes) originate in the bone marrow
• B lymphocytes


  • Remain in the marrow to mature

  
• T lymphocytes


  • Travel to the thymus to complete their maturation
• Secondary or peripheral lymphoid organs

  • Lymph nodes
  • Spleen
  • Mucosal Associated Lymphoid Tissues (MALT)
• Secondary or peripheral lymphoid organs

  • Specialized to trap antigen
  • Allow to initiation of adaptive immune responses
  • Provide signals that need for recirculation of lymphocytes

  
• Branches of immune system

  • Innate immunity
  • Acquired Immunity

  
• Innate immunity


  Antigen-nonspecific defense mechanisms, host uses immediately or within several hours after exposure to almost any invador

  
• Components of innate immunity

  • Anatomical barriers
  • Mechanical removal
  • Chemical factors
  • Biological factors

  
• Acquired Immunity


  Acquired, selective and mediated by lymphocytes. Specific immune response amplifies the mechanisms of natural immunity and enhances there function, particularly upon repeated exposures to the same foreign antigen

  
• Lines of defense to combat microbial invasion

  • Fight the infection outside of the cells
  • Fight the infection inside the cells
  • Inflammation
• Inflammation

  Part of the body's defense mechanism, by which the immune system recognizes and removes harmful and foreign stimuli and begins the healing process

  
• Types of inflammation


  • Acute inflammation
  • Chronic inflammation
• Acute inflammation


  • The response to sudden body damage, such as cutting of finger. To heal the cut, the body sends inflammatory cells to the injury
• Chronic inflammation

  • Can continue for months or years. It either has or may have links to various diseases, like: diabetes and cardiovascular disease (CVD)
• Oral immunity


  • Integrity of oral mucosa
  • Role of saliva
  • Role of Gingival crevicular fluid
• Integrity of oral mucosa

  • The intact stratified squamous epithelium act as a mechanical barrier against oral M.O. The continuous shedding by exfoliation of epithelial squamous limited microbial colonization of the surface
• Role of saliva


  • The flow of saliva has a mechanical effect as it remove the microorganisms from mucosal and tooth surfaces
• Role of Gingival crevicular fluid


  • An inflammatory exudate derived from the periodontal tissues. It is composed of serum and locally generated materials such as tissue breakdown products, inflammatory mediators, and antibodies directed against dental plaque bacteria