Response to Infection

Pathogens

Disease causing organisms

Bacteria

Microscopic living organisms, usually one-celled, that can be found everywhere

Virus

Able to multiply only within the living cells of a host and therefore tend to target specific tissues in the host

Lysozyme

An enzyme that kills bacteria, found in tears, saliva, sweat, nasal secretions and tissue fluid

Leucocyte

A white blood cell

Phagocyte

Any leucocyte that is capable of engulfing and digesting micro-organisms and cell debris

Macrophages

Can carry out phagocytosis and release substances which destroy micro-organisms

Phagocytosis

The process of a leucocyte engulfing and digesting micro-organisms and cell debris

Bacteriophage

Viruses that infect and replicate only in bacterial cells

Lymphocytes (B and T cells)

A cell produced in bone marrow and some lymphoid tissue that circulates through tissue, blood and lymph.

Histamine

A chemical that increases blood flow by increasing capillary permeability and causing blood vessels to dilate

Heparin

Prevents immediate clotting