White blood cells
- There are two types of white blood cells. Phagocytes and Lymphocytes. They both get rid of pathogens.
- Phagocytes get rid of pathogens by phagocytosis:
- Step 1: encounters foreign body or pathogen
- Step 2: engulfs the foreign body or pathogen
- Step 3: breaks down with enzymes
- This is a non-specific immune response and will engulf ANY foreign body.
- Lymphocytes, specifically B-Lymphocytes produce antibodies to fight pathogens.
- Step 1: B-Lymphocyte encounters the pathogen.
- Step 2: The cell produces antibodies matching the antigen on the pathogen.
- Step 3: The antibodies fit onto the antigens and cause them to “clump”
- Step 4: The pathogen is absorbed and digested by the white blood cells.
Primary response
- When a foreign body first enters the system, the antigen is not recognised immediately. It takes the body a while for the lymphocytes to multiply and secret enough antibodies to destroy the pathogens.
- Memory lymphocytes remain in the blood for a long time and remember a specific antibody.
- The person becomes immune to that particular pathogen; their immune system can now respond quickly to an infection.
Secondary response
- If the same pathogen enters again, the immune system will produce a quicker and stronger immune response.
- The secondary response often gets rid of pathogens before you show any symptoms.