Question

urgent!

1. what is the equilibrium potential of Ca?

ECF 1.0mM
ICF 10-7mV

2. How will pacemaker potential change when Ik current at SA increases?

Answer 1

1) E = 30.77 mv/ 2 ( log ECF/ICF)

z = 2

at z = 2 the constant is halved into 30.77

E= 15.4 (log 1/10-7)

E= 107.8 mV

2) the SA nodes have no specific resting membrane potential like Neurons. from - 60mV it drifts upward resulting depolarization. this depolarization results pacemaker potential. when ik current is increased at SA node, there will be difference in spontaneous depolarization rate. this will result some Abnormalities of the normal function of the pacemaker.

the increase of ik current across th cell membranes that occurs at the end of one action potential and the next action potential.