In myelinated neurons, the ion exchange of an action...

In myelinated neurons, the ion exchange of an action potential does not actually occur in myelinated regions of the axon. The nodes of Ranvier are sites where the action potential regenerates. a. Explain why an action potential will not regenerate if the nodes are too greater than 1.5 mm apart. (the answer not because they are too far apart). b. Explain why a demyelinating disease such as multiple sclerosis also causes the action potential to die out and not reach the axon terminal of the neuron.

Transcript

00:01 Hello students, in this question it is being said that in myelinated neurons, the ion exchange of an action potential does not occur in myelinated regions of the axon.

00:12 The nodes of ranvier are sites where the action potential regenerates.

00:18 Now the question asked is, explain why an action potential will not regenerate if the nodes which is nodes of ranvier are 2 greater than 1 .5 millimeters.

00:37 The maximum distance which is between the nodes of ranvier which could be possible in terms of action potential is 1 .5 millimeters apart.

00:53 More than that, there will be very low action potential or there will be no action potential at all.

01:00 So what limits or what is the limitation if there is more than 1 .5 millimeter distance between the two nodes of ranvier? it can be explained using the cable theory.

01:23 As we know that the action potential propagates along the membrane of the axon and its stripping voltage -gated channel that renew the influx of ions into the stream at the nodes.

01:50 There are no ion channels along the myelin sheath so the current is able to zip through that area.

02:01 So basically there is no renewal of action potential but there is no loss due to the leak of ion either.

02:12 So there is no renewal of the action potential along the myelinator sheath and there is also no loss due to leak of ion.

02:23 So since there is no influx of ion from outside of the membrane until the next node, the capacitance and resistance of the membrane is exponentially decaying.

02:56 Due to the capacitance and resistance, the voltage is becoming lower and lower which means that the voltage is decaying...

Question

Please give Ace some feedback