Question

#1 Engineer a neuron that has a positive resting potential but propagates a signal through its axon. You can design (1) your own ion pump and determine directionality of the pump (2) design voltage gated channels. You can use hypothetical negative N1-, N2-, etc.. and positive ions P1+, P2+, etc… #2 describe 3 channel related diseases; how does the mutation affects the function of the channel and what are the implications? What are the clinical symptoms exhibited by the affected individuals? (~ one paragraph for each condition)

Answer 1

1)

• Normally action potential is triggered only when the resting potential of the membrane which is negative increases and becomes positive causing the peak action potential.
• Here the sodium channel pump opens allowing the influx of Na+ ions causing inside of the membrane more positive. Thus resting potential increases from -70 to +40mV.
• Suppose , as mentioned above if the resting membrane potential is positive , influx of more positive ions P1 causes increases the resting membrane potential causing it more positive .
• This increase in membrane potential cause release of action potential.

2)

• Mutations in channels causes , loss or gain of function of particular channel.
• Loss of channel causes permanent closure of channels and gain of function causes permanent open of ion channels .
• Cystic fibrosis is caused by loss of function chloride channels.
• Cardiac arrthymia caused by loss of function of potassium channels.
• Paramyotonia and epilepsy is caused by gain of function of sodium channels.