Our body reacts to the different inputs it gets from the surroundings due to the nervous system. The nervous system is a network of nerves that are spread out to the smallest part of the body so that every part can react to a stimulus. There are about 100 billion neurons in our Central nervous system. A stimulus can be mechanical, chemical, electrical or thermal and the body responds to this stimulus as there is a change in the physio-chemical balance at the cell membrane. This disturbance at the cell membrane is called membrane potential. When there is difference in the electric potential, the signal travels from one neuron to the other through axons. Some axons are myelinated and some are not. The myelinated axons have a couple of breaks in the myelin sheath and these breaks are called as Nodes of Ranvier. When the action potential, passes down the myelinated axon, at the nodes of Ranvier the signal jumps across the nodes and this helps the signal to travel faster than if it were to travel down a non-myelinated axon. This jumping of signals across the nodes of Ranvier is called Saltatory Conduction. Conduction and nerve impulses work in correlation.
Earlier when the experiments were carried out to test nerve impulses, scientists always stayed away from using conduction procedure for the fear of electricity. Now, it has been found out that the same experiment can be carried out by passing electricity through 3mm of cocaine and ringer solution and it resembles the reaction produced by the human body when a very mild electric current is passed through it.
Nerve impulse conduction is nothing but the self motivated and highly active spreading process in which the impulse travels along with the nerve axon in situation where velocity and amplitude are constant. Other factors responsible for carrying successful propagation of nerve impulse during conduction are spherical flow of the current, consecutive depolarization of eletrotonic.
Nerve impulse termed as Saltatory conduction is an impulse. The saltatory conduction helps the action potential to move with efficiency and speed. This whole action of salutatory conduction is carried out in our human body, to be more specific in the myelin nerve fibers. The name salutatory conduction has evolved from the French word, "saltare" which means leap. Saltatory conduction performs the important function of improving the energy efficiency level in the nervous system.
Neuron and muscle cell signals conducted via electric impulse is termed as an action potential. The highlighting feature of an action potential is that it simply affects the movement or leaps of electric signal from one step to the another and do not travel the whole nerve length.
Myelin is manufactured by Central nervous system and is a white component made up of proteins and lipids. During saltatory conduction, myelin performs the function of insulator. As an insulator myelin takes care that the electric charges are not leaked out through the axon membrane. Action potentials whereas move freely via nerve fibers. Since it is not possible for the electrical impulses to pass via axon membrane’s covered portion, the electric current performs the action potential by jumping to the neighboring node.
Saltatory conduction is highly advantageous for Central nervous system. It enhances velocity by 30 times than the velocity which prevails during continuous conduction. Since this type of conduction uses restricted electric current, only very small measure of ions are leaked out via membrane due to which metabolic energy is saved. This is beneficial because approximately 30% metabolic energy is used up by the human body. Apart from vertebrates like humans, even invertebrates such as shrimp and earthworm exhibit saltatory conduction.
During the process when action potential is leaping from one node to another, the movement is at a very high velocity due to which the axon’s diameter remains constant. Research has shown that if a mechanical injury occurs on a numb or anesthetized part, the process of nerve conduction is halted. Similarly, if an anesthetic solution is applied to the myelin nerve fiber, its energy level does not get affected.