Abstract
In recent years, a vast body of information has been
accummulated on the electrical properties of biological
membranes. It has been found that electrical potential
differences occur across them, that ions can penetrate them
and that they have a quite high resistance to the flow of
electric current through them. Analysis of this information
has revealed that there is no general theory of membrane
phenomena which can explain all of it. As well as these
general phenomena, some cell membranes, particularily those of
nerve cells, are capable of producing a temporary and
localised change in membrane potential and membrane resistance,
which is propagated along the membrane as an electrical
impulse.
An excitable membrane is nowadays regarded as being one of
the basic functional units in a biological computer or control
system and in view of its fundamental importance, it is hardly
surprising that probably more information is available on the
electrical properties of nerve membranes (particularily the
giant nerve from the squid) than on any other membrane. A
great deal is now known about the action potential, as the
phenomenon of exitability is called, and despite the
illuminating hypothesis of Hodgkin and Huxley, the problem of
the exact physical chemical mechanism of excitability remains
to be solved.
All nerves are capable of conducting impulses and so are
muscle cells; so also are certain. giant plant cells of the
Characeae. Over the years the development of knowledge about
the action potential in nerve has proceeded side by side with
the study of the action potential in these plant cells and in
this thesis the giant plant cell Nitella translucens has been
chosen for studying biological membranes in both their resting
and excited states. This chapter is concerned mainly with the
theoretical basis of electrical phenomena in membranes in
general, and with the electrical properties of biological
membranes in particular.
