Biomedical Engineering Reference
In-Depth Information
Fig. 4.
Action potentials, calcium transients, and transmembrane ionic currents during 800 ms
of spontaneous electrical activity in the rabbit SA node models of Bristow and Clark [6],
Irisawa and Noma [36], and Noble and Noble [61].
a
Membrane potential (
V
m
).
b
Intracellular
free calcium concentration ([Ca
2+
]
i
).
c
Net transmembrane current (
I
m
).
d
Delayed rectifier
potassium current (
I
K
) and slow inward or calcium current (
I
si
and
I
Ca
, respectively).
e
Fast
sodium current (
I
Na
) and hyperpolarization-activated current (
I
f
).
f
Sodium-potassium pump
current (
I
NaK
) and sodium-calcium exchange current (
I
NaCa
).
g
Net background current (
I
b
) and
its calcium, potassium, and sodium components (
I
b,si
or
I
b,Ca
,
I
b,K
, and
I
b,Na
, respectively).
