Plan of Protection Immunity

Plan of ProtectionImmunity is the ability to defend against infectious agents, foreign cells and abnormal cells eg. cancerous cells 

  • 1st Line of defense – Block entry
  • 2nd Line of Defense – Fight Local Infections
  • 3rd Line of Defense – Combat Major Infections 

Nonspecific and Specific Defense Systems

work together to coordinate their responses 

Nonspecific (Innate) Response – responds quickly, fights all invaders and consists of:

  • First line of defense – intact skin and mucosae and secretions of skin and mucous membranes prevent entry of microorganisms
  • Second line of defense – phagocytic white blood cells, antimicrobial proteins, and other cells
  • Inflammatory response process is key  
  • Inhibit invaders from spreading throughout the body

Specific Response (Adaptive) Response

Takes longer to react, works on specific types of invaders which it identifies and targets for destruction 

  • Third line of defense – mounts attack against particular foreign substances
  • Lymphocytes and Antibodies 
  • Works in conjunction with the nonspecific or innate system

Nonspecific (Innate) Response – fight all invaders  

First line of defense – Non specific barriers to block entry 

  • Skin provides an impervious barrier – physical or mechanical barrier 
  • Mucous membranes line the entrances of the body  and produce mucus which traps foreign particles and directs them out of the body – physical or mechanical barrier   
  • Nasal hairs trap dirt and dust while microscopic cilia line some mucous membranes helping to trap foreign particles
  • Gastric juice, vaginal secretions and urine are acidic fluids which provide protection
  • Natural flora (harmless bacteria) in the intestine and vagina prevent pathogens from growing 
  • Tears, saliva and sweat possess some anti-bacterial properties

Cerumen or ear wax protects the ear canal by trapping dirt and dust particles

Second line of defense – Fight local infection with Inflammation Process

  • Begins as soon as the first line of defense is violated
  • The response is a non-specific, immediate, maximal response to the presence of any foreign organism or substance and involves no immunological memory 
  • Phagocytosis is an important feature of cellular innate immunity performed by cells called ‘phagocytes’ that engulf, or eat, pathogens or particles
  • Phagocytes – types of immune cells involved in phagocytosis – Produced throughout life by the bone marrow
  • Scavengers – remove dead cells and microorganisms
  • Complement proteins activate other proteins in a domino fashion resulting in a cascade of reactions which attract phagocytes to the site of the invasion, bind to the surface of microbes to insure WBC’s can phagocytize the microbe and produce holes in the bacterial cell walls and membranes  

The Inflammation Process releases histamines  causing redness, pain, swelling, and heat