The transmission of the nerve impulse is a electrochemical phenomenon that occurs in nerve cells and makes the nervous system work. It is the result of changes in electrical charges on the membrane of neurons, cells specialized in processing information.
How Does Nervous Impulse Propagation Occur?
The nerve impulse is an electrochemical phenomenon, therefore it involves chemical and electrical aspects.
Nerve impulse transmission in the neuron
O electrical aspect and the propagation of a signal within a neuron. It usually starts in the cell body and is transmitted towards the axons.
O chemical phenomenon consists of synapses, which are the transmission of impulse from one cell to another, through substances called neurotransmitters.
Action Potential
When neurons are at rest, their membrane is negatively charged with respect to their outside. There is an electrical potential difference (about 70 millivolts) called the resting potential.
happens to inversion of electrical charges inside the membrane quickly and abruptly, which becomes positive in relation to its outer surface.
These changes in electrical charges produce a difference in electrical potential between the inside and outside of the membrane, which is called the action potential.
This electrical change occurs in a small area and spreads throughout the cell. This event is called depolarization and lasts for a few seconds, then returning to rest, it is the repolarization.
Sodium-Potassium Ion Pumps
Scheme of ion pumps and protein channels generating action potential in a part of the neuron
Atelectrical charges travel on neurons as ions, mainly sodium (Na+) and potassium (K+). These ions cross the neuron plasma membrane through protein channels and ion pumps, which are embedded in the phospholipid membrane bilayer.
THE sodium-potassium pump inserted in the membrane, it moves the ions against its concentration gradient, it takes the sodium and puts the potassium inside the cell and for this there is an energy expenditure.
You protein channels, in turn, are pores in the membrane surrounded by proteins that allow diffusion without energy expenditure. These channels are generally specific to the ion types.
Learn more about Sodium and Potassium Pump.
Synapses
Synapses occur between the termination of a cell's axon and the dendrites of a neighboring cell. through the neurotransmitters, which are chemical mediators charged in vesicles, the signal is chemically conducted and stimulates the signal in the neighboring neuron.
The action potential happens again and so the nerve impulse continues to propagate in the network of neurons.
Test your knowledge with Exercises on the Nervous System.
