Leucocytes or leukocytes, colloquially known as white blood cells (WBCs), are clear, colorless cells that circulate in the blood and lymph and are integral part of the immune system.
There are two lymphoid tissue types: Primary Lymphoid tissues, comprising the bone marrow and thymus where leucocytes are synthesized
Secondary lymphoid tissues, comprising the spleen, lymph nodes and mucosa associated lymphoid tissues (MALT)
Secondary lymphoid tissues contain the mature leucocytes that react to infection, triggering an immune response.
There are multiple forms of leucocyte.
- Male, D (2007), Immunology, Milton Keynes, The Open University/Milton Keynes, The Open University