Function of neuron

                          

Communication within neuron: The neuron receives the information from anon of other neuron or through sense organs. When neuron is at rest, there is tiny negative electrical charge (-70 millivolt) across the cell membrane. This electrical charge is produced because several negative charge ions (like cl, protein molecules) and positive charge ions exist in different concentration inside and outside the membrane. As the concentration of negatively charged ions is much than the positive charge ions inside of the cell membrane, the charge inside the membrane is slightly negative compared to the outside of he cell membrane. The electrical potential develop when neuron is at rest is called the resting potential. When neuron is stimulated either by chemical message from other neurons or directly by heat, light pressure etc. it produces a type of single called graded potential (that results from the simulation of dendrite or cell body). Strength of the graded potential varies with the intensity of the stimulus and cause local flow of current which decrease with distance from the stimulus point. It can cause either a depolarization (an excitatory response that may lead to and action potential) or hyper polarization (an inhibitory response which makes it harder for an action potential to occur) depending on the ion let in(or out). The incoming information is conveyed over short distances usually up to cell body. If it caused depolarization or if the magnitude of incoming information exceeds the threshold, action potentials generated. Action potential is a rapidly moving wave of depolarization that travels along the cell membrane of a neuron (Baron, 2003). Action potential is an “all or no” phenomena. During action potential, the sodium ions are briefly allowed to enter inside the cell membrane and negative charge ions are allowed to pass outside the membrane. The influx of sodium ion rapidly moves through out the length of the axon, thus transmitting the incoming information to the terminal branches. The neuron then actively pumps the sodium ion outside the membrane, thus regaining its resting potential. At this phase neuron does not receive any other information. This phase is called refractory phase. In this way information is communicated within the neuron.