OCR B1C: Disease

Pathogen: A disease-causing microbe.

 There are four types of pathogen:

• Bacteria (e.g. Sore throats, ear aches, diarrhea/sickness)
• Virus (e.g. Influenza, HIV/AIDS, bird flu)
• Fungi (e.g. Athletes foot, thrush)
• Protozoa (e.g. Malaria, Amoebic dysentry, taxoplasmosis)

Antibiotics will only work with bacterial illnesses.

Infectious diseases can be passed on from creature to creature (contagious). Examples:

• Chicken Pox
• Malaria
• Influenza
• TB

Non-infectious diseases can not be passed on from creature to creature (non-cotagious). Examples:

• Ezcema
• Dementia
• Ceoliac
• Asthma

Every pathogen will have antigens on it's surface. It is the antigens that trigger disease and the immune system's response. The antigen is specific to the receptor of the cell it is wanting to infect, like a key and lock. The cell then lets the pathogen enter, and then the pathogen hi-jacks it, causing the cell to make copies of the pathogen, which are then released to infect other cells. This process continous until all the cells in that area have been hi-jacked, so it moves onto another area of the body, or the pathogen is stopped by the immune system. 

Antigens trigger 3 types of immuns system responses:

• Phagocytes: White blood cells which engulf and digest pathogens.
• Antibody Production: White blood cells produce antibodies which 'fit' onto the pathogen exactly. The antibody destroys the pathogen.
• Toxin Production: White blood cells release a toxin that destroys the pathogen.

Memory cells: When the pathogen has been destroyed, the body keeps a copy of the antibody so if…