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Fig. 1.2
Electric equivalent of the cell's membrane
Fig. 1.3
Equivalent circuit of cell's membrane
Voltage V
M
is computed from the Goldman-Hodgkin-Katz equation and C
M
is
the membrane's capacity. The normalized membrane capacity (capacity per cm
2
)is
noted as c
M
. Considering the equivalent circuit of Fig.
1.3
it holds that
dq
dt
I D
(1.18)
and
I
k
D
V
M
E
k
R
k
) I
k
Dg
k
.V
M
E
k
/
(1.19)
where g
k
is the conductance normalized per unit of surface.
The above holds for one channel of ions. Assume now that there are N
k
channels
of ions. The aggregate resistance of the circuit is N
k
R
k
D r
k
. Then the current
through the ions' channel is written as
