Neuronsand their Respective Functions
Neuronsand their Respective Functions
Bodiesof different animals are complex and their functions are facilitatedby activities of various systems and organs. The term neuron refersto a nerve cell that plays the critical role of facilitating thetransfer of signals from the peripheral parts of the body to thebrain as well as the spinal cord (Ramon, 2015). They are specialtypes of cells that have the capacity to transfer signals through theprocesses of chemical and electrical excitation. They are classifiedin the group of the most specialized types of cells since they carrydifferent functions, but in a highly coordinated manner. This paperwill provide a discussion of different functions of neurons andmechanisms through which they accomplish their roles.
Neuronsas Components of the Nervous System
Thebodies of all vertebrates have comprehensive nervous systems. Theyare classified into peripheral and CNS. The CNS is made of the spinalcord and the brain. Its main function is to process information. Theperipheral nervous system is comprised of the different types ofneurons. The information that is processed within the CNS is suppliedby neurons that form the PNS (Kibiuk, 2012). However, some neuronshave long extensions that run from the CNS to skeletal muscles wherethey regulate their functioning and coordination.
BroadClassification of Neurons on the Basis of the Roles that they Play
Neuronsare put into three classes depending on the roles that they play inthe body. The first class is comprised of the sensory neurons. Theprimary role of all neurons that are classified as sensory is totransfer information about events that are taking place outside thebody and take it to the CNS where it is processed (Ramon, 2015). Forexample, it is the role of the neurons with endings in the fingertipsto collect information about the temperatures of an object that anindividual touches and to notify the CNS whether it is hot or cold.
Thesecond category is comprised of the motor neurons. They act as theintermediaries between other types of neurons and different parts ofthe body. The main role is to transfer information from other classesof neurons to glands, organs, and muscles (Ramon, 2015). The role ofmotor neurons is confirmed by the reflect actions that take place invarious parts of the body under different conditions. For example,the motor neurons play a critical role in innervating the relevantmuscles in human, which enables an individual to remove the hand froma hot object.
Thethird category is comprised of interneurons. Interneurons exist inlarge number in the body compared to other categories. They connectneurons to each other and facilitate the process of sharinginformation. The role of interneurons can be explained using theprocesses that occur when one touches a hot object. The informationcollected by sensory neurons at the tips of one’s finger ischanneled in two directions. Some interneurons take the informationto motor neurons. Others pass the information to the brain where itis interpreted as pain (Ramon, 2015).
Theinterneurons’ main function is to facilitate the processing ofinformation in complex as well as simple circuits within the brain. Acombination of interneurons that are located in the brain helpindividuals to draw the conclusion that items that are extremely hotare not supposed to be touched. They also store that information forthe future reference, especially when one comes across similarobjects.
FunctionalClassification of Neurons
Apartfrom the basic classification of neurons that is based on roles thatthey play in the body, they may also be put into different groupsdepending on the mechanisms in which they function. One of theseclassifications is based on the mechanisms through which they act onthe rest of the neurons. A neuron can cause an effect on another oneby releasing a substance known as the neurotransmitter. Aneurotransmitter acts as a key that binds and unlocks the chemicalreceptors (Delgado, 2013). A decrease in functionality occurs whenneurotransmitters unlock inhibitory neurons. An increase in thefunctionality takes place when neurotransmitters unlock theexcitatory receptors.
Someof the most common types of neurotransmitters that are released byneurons with the objective of carrying out specific functions includeGABA and glutamate. Neurons release glutamate when there is a need tocause excitatory effects on ionotropic receptors and a modulatoryimpact on metabotropic (Delgado, 2013). In addition, neurons releaseGABA when inhibitory effects are required. It is estimated that over90 % of all neurons that are located in the brain function byreleasing either the GABA or glutamate neurotransmitters (Delgado,2013).
Thereis no clear distinction between inhibitory and excitatoryneurotransmitters. This is because a single neuron that functionsthat releasing a given type of neurotransmitter can cause aninhibitory impact one on receptor and cause excitement in another.However, the type of function or the effect that a given neuron islikely to cause can be predicted using the protein that it expresses.Neurons that are classified on the basis of the type ofneurotransmitters that they produce include GABAergic, dopaminergic,cholinergic, serotonergic, and glutamatergic.
Connectivitybetween the Neurons
Neuronscarry out their functions by passing information to one another or tothe rest of the body organs. The sharing of information, which is thebasis of communication, is facilitated by effective connections thatexist between the neurons. Neurons link to each other in a systematicway. The axon of one neuron connects to the dendrite of the adjacentone (Delgado, 2013). This process of connection is referred to assynapses.
Thetotal number of dendrites varies from one type of neuron to another.However, all of them are able to receive thousands of synapses,irrespective of their numbers. Synapses can increase or reduceactivity in the target neuron depending on whether it is inhibitoryor excitatory in nature. Some neurons are able to carry out theirfunctions by communicating with each other through electricalsynapses. This type of nerves has conductive junctions thatfacilitate the flow of a current between the neurons (Delgado, 2013).
Anatomyand Functions of Different Parts of Neurons
Eachpiece of the neuron is made up of different parts where each of themhas its own function. The axon is a single process that extends awayfrom the body of a neuron. The main function of the axon is totransfer electrical signals from the soma to adjacent neurons (Gage,2015). Its effectiveness is determined by myelin sheaths that runalong its entire length. The primary functions of the myelin sheathinclude the insulation of the fiber that forms the nerve and itsprotection. It also increases the rate at which the nerve impulsesare transmitted.
Dendritesare receptors that are fiber-like in structure. Their function is toreceive signals that originate from the nearby neurons (Gage, 2015).However, they do not touch the nearby neurons. They leave a gapreferred to as synapses that separate the neurons. Dendrite transfersthe nerve impulses from neurons to other cells of the body. The firsttwo roles of neurons (including the reception and processing ofdifferent pieces of information) take place in the dendrites.Dendrites have the capacity to carry both the inhibitory andexcitatory signals, which imply that they can enhance or limit thefunctions of the cells that receive their impulses.
Theterm nerve is used to refer to a bundle that contains about 100-1000axons, blood vessels, and connective tissues. Nerve cells areexcitable, which implies that their function is to facilitatecommunication between neurons through electrical stimulation (Gage,2015).
Theterm "nodes of ranvier" refers to gaps that occur atspecific intervals within the myelin sheath of the nerve fiber. Thefunction of these gaps is to facilitate the entry and exit ofnutrients and water into and out of the neurons. They also facilitatethe processes of re-polarization and de-polarization of the membraneof nerve cells, which enhances the movement of signals in theneurons. Neurons have many parts, but the aforementioned ones areresponsible for their effectiveness in carrying out differentfunctions.
Neuronsare part of the nervous system and their primary function is tofacilitate the communication between the peripheral part of the bodyand the CNS. Although most of the neurons are located in theperipheral nervous system, the motor neurons are quite long and theyextend from the skeletal muscles to the CNS. Individual parts of theneurons (including axon, myelin sheath, dendrite, soma, neurilemma,and nodes of ranvier) have their own functions. However, theactivities contribute towards the overall functioning of the neurons,which include the reception of signals and the integration of theincoming impulses. They also relay the signals to the nearby cells,including other neurons, glands, and muscles. Therefore, the keyfunctions of individual neurons can be reflected in their respectiveanatomy.
Delgado,C. (2013). Glutamate and GABA in appetite regulation. FrontEndocrinol,4 (103), 1-8.
Gage,H. (2015). Neuroscience: The study of the nervous system and itsfunctions. TheJournal of American Academy of Arts and Sciences,144 (1), 1-5.
Kibiuk,V. (2012). Parts of the nervous system. BrainFact organization.Retrieved October 12, 2016, fromhttp://www.brainfacts.org/brain-basics/neuroanatomy/articles/2012/parts-of-the-nervous-system/
Ramon,S. (2015). Overview of neuron structure and function: How do you knowwhere you are right now? KhanAcademy.Retrieved October 12, 2016, fromhttps://www.khanacademy.org/science/biology/human-biology/neuron-nervous-system/a/overview-of-neuron-structure-and-function