Question

Explain the need for saltatory conduction and how myelination and axon diameter affect rate of conduction – you can do this as an illustration. Make sure in your answer you include: axon, axon hillock, axon terminal, original action potential, new action potential, Schwann cell, myelin, node of Ranvier, depolarization, refractory DO NOT DEFINE THESE TERMS INDIVIDUALLY

please type the answer.

Answer 1

Ans: Needs for Saltatory conduction:

Saltatory conduction is the propagation of action potentials along myelinated axons from one node of Ranvier to the next node, which is increasing the conduction velocity of action potentials. The uninsulated nodes of Ranvier are the only places along the axon where ions are exchanged across the axon membrane, which regenerating the action potential between regions of the axon that are insulated by myelin, unlike electrical conduction in a simple circuit.

The velocity at which an action potential propagates down an axon is limited by the speed at which ion channels open and close, it is slow compared to the physical conduction of electricity in a wire. In such cases some neurons, action potentials must travel significant distances to reach the effector junction where coordinated function is dependent on signals reaching the target quickly, vertebrates accelerate action potential propagation by employing saltatory conduction. But, in myelinated neurons, ion channels are located at the Nodes of Ranvier, and it is only at these sites where action potentials are regenerated. The myelin sheath provides an insulation that increases membrane capacitance and, thus, diminishes decremental conduction. Therefore, current propagates from nodeto node in a manner more closely resembling a wire.

* It increasing inward current by increasing the axon diameter and increased Conduction Velocity as a Result of myelination. The rate of action potential conduction limits the flow of information within the nervous system which increases nerve conduction velocity.

For e.g, whereas unmyelinated axon conduction velocities range from about 0.5 to 10 m/s, myelinated axons can conduct at velocities up to 150 m/s.