immune system

The immune system (IS)

Caused by - pathogens (virus, bacteria, fungus, protozoa)

Virus - spread v.fast, direct contact, blood sharing, air breathing

Bacteria - slower spread, hygiene, overcrowding, antibiotic resistance bacteria, direct contact)

Fungus - damp, dark, warm, very slow spread, outside contaminate)

Phagocytes

• Non specific IS (cillia, eyelashes, PH changes) & specific IS

• Non specific = general defence & phagocytes

• Important bridge between both immune systems 

– destroys any ‘foreign’ cell but carries out ‘antigen presentation’ (helps specific IS)

Antigen presentation 

1. Phagocyte digests a pathogen 

2. Pathogen(antigen) gets to the surface of the phagocyte

3. Phagocyte presents the antigen to a helper T cell 

4. Helper T  cell is activated 

T-lymphocytes

• Comes from bone marrow -> thymus gland…