What does the immune system do?
The immune system is one of the most important parts of the body. Its your body’s defence mechanism, and works 24/7. But you cannot see it, touch it or feel it.
The immune system protects the body from harmful substances and germs by recognising and responding to antigens:
Identifying antigens
The immune system identifies antigens, which are substances on the surface of cells, viruses, fungi, bacteria or parasites. These are the four main causes of infection.
Antigens can also be non-living substances like toxins, chemicals, drugs, and foreign particles.
Responding to antigens
The immune system responds to antigens by destroying or trying to destroy them.
Keeping a record of previous germs
The immune system remembers every germ it has defeated so it can recognise and destroy it quickly if it enters the body again.
Protecting normal healthy tissue
The immune system recognises and protects healthy tissue, whilst defeating disease-causing germs.
What is the immune system made up of?
The immune system is made up of a complex network of organs, cells, and proteins that work together.
- Organs include – the spleen and bone marrow (and parts of all organs actually)
- Cells – include – two forms of white cell:
- Granulocytes (e.g. neutrophils, eosinophils, and basophils)
- Mononuclear cells (e.g. monocytes, and lymphocytes (T cells and B cells))
- Proteins – include antibodies and cytokines.
Two types of immunity
The immune system has two types of immunity: innate and adaptive.
- Innate immunity – is the body’s first line of defense and provides an immediate response to pathogens
- Adaptive immunity – is specific and involves B cells and T cells.
