Download Cell Signalling and communication between cells.

Cell Signalling and
communication between cells.
• Key definition:
Cell signalling is the communication
between cells that allows effective
coordination of a response.
Cell signalling in the immune
system.
• Cell signalling is vital in the immune system, it
helps to activate all the different types of white
blood cells that are needed.
Communication is achieved through cell surface
molecules, and through the release of hormonelike chemicals called ‘cytokines’.
To be able to detect these molecules the cell must
have a surface receptor , the surface receptor must
be specific, this is to ensure that they only bind
and respond to that specific molecule.
• Cytokines are chemical signals that act as
instructions to their target cells, there are a
range of cytokines that can be released.
They bind to the specific receptors on the
target cell, which then alters the behaviour
of the target cell.
• Pathogens carry an antigen on its cell surface, they
act as markers, they enable it to be detected by our
body cells, as a ‘foreign cell’. Our own cells also
carry antigens, but they are recognised as ‘self’. In
order to avoid destroying any ‘self’ cells, the
immune system will contain no cells with
complimentary receptors for our own antigens,
this means no ‘self’ cells can stimulate an immune
response.
• A foreign antigen will stimulate a response,
the response results in the production of
‘antibodies’ from the B-lymphocytes.
The immune system needs to manufacture
an antibody for each antigen recognised by
the immune system, so the antibodies can
attach to the antigen causing them to
become harmless.