Premium Essay


In: Science

Submitted By ellebyram08
Words 1496
Pages 6
A neuron (/ˈnjʊərɒn/ nyewr-on or /ˈnʊərɒn/ newr-on; also known as a neurone or nerve cell) is an electricallyexcitable cell that processes and transmits information through electrical and chemical signals. These signals between neurons occur via synapses, specialized connections with other cells. Neurons can connect to each other to formneural networks. Neurons are the core components of the brain and spinal cord of the central nervous system (CNS), and of the ganglia of the peripheral nervous system (PNS). Specialized types of neurons include: sensory neuronswhich respond to touch, sound, light and all other stimuli affecting the cells of the sensory organs that then send signals to the spinal cord and brain, motor neurons that receive signals from the brain and spinal cord to cause muscle contractions and affect glandular outputs, and interneurons which connect neurons to other neurons within the same region of the brain, or spinal cord in neural networks.
A typical neuron consists of a cell body (soma), dendrites, and an axon. The term neurite is used to describe either a dendrite or an axon, particularly in its undifferentiated stage. Dendrites are thin structures that arise from the cell body, often extending for hundreds of micrometres and branching multiple times, giving rise to a complex "dendritic tree". An axon is a special cellular extension that arises from the cell body at a site called the axon hillock and travels for a distance, as far as 1 meter in humans or even more in other species. The cell body of a neuron frequently gives rise to multiple dendrites, but never to more than one axon, although the axon may branch hundreds of times before it terminates. At the majority of synapses, signals are sent from the axon of one neuron to a dendrite of another. There are, however, many exceptions to these rules: neurons that lack dendrites, neurons…...

Similar Documents

Premium Essay

Circular Nervous System

...put food in our mouth, it immediately causes the release of saliva from the salivary glands. The Unit of Nervous System: Neuron : The units which make up the nervous system are called nerve cells or neurons. So, neuron is the structural and functional unit of the nervous system. We can now say that nervous system is made of special cells called neurons. Neuron is the largest cell in the body (which looks like an electric wire). Neurons contain the same basic parts as any other animal cell but their structure is specially adapted to be able to carry messages over large distances in the body quickly. The neurons carry messages in the form of electrical signals called electrical impulses or nerve impulses. A neuron (or nerve cell) has three components: (ii) Dendrites, and (iii) Axon. The cell body of a neuron is like a typical animal cell which contains cytoplasm and a nucleus. A number of long and thin fibres are stretching out from the cell body of a neuron. They are called nerve fibres. The shorter fibres on the body of a neuron are called dendrites. The longest fibre on the cell body of a neuron is called axon. The axon has an insulating and protective sheath (or cover) of myelin around it (Myelin is made of fat and protein). It is clear that both dendrites and axon arise from the cell body of a neuron. The messages which the neurons transmit in the nervous system are in the form of electrical impulses called nerve impulses (or just impulses). The......

Words: 758 - Pages: 4

Premium Essay

Neuron Paper

...Neurons are the specialized cells of the nervous system. There are three types of neurons: sensory neurons, motor neurons, and interneurons. Sensory neurons are involved with sensation, such as feeling pain, and they relay messages to the brain or spinal cord. Motor neurons transmit impulses from the central nervous system to activate parts of the body, such as muscles or glands. Interneurons receive signals from sensory neurons and from hormones and act like bridges transferring messages between the sensory neurons and motor neurons. The central nervous system (brain and spinal cord) is made almost entirely from interneurons. They are what make complex reflexes and the higher associative functions required for learning and memory possible. Communication between neurons, also termed neurotransmission or synaptic transmission is accomplished by the movement of chemicals and electrical signals across a synapse. Interneurons function by receiving information or messages (input) from other neurons, processing the information, and then sending this ‘output’ to other neurons through synapses. There are electrical synapses as well as chemical synapses. The electrical synapses are involved with long distance rapid communication. Chemical synapses process neurotransmission involving chemical messengers, or neurotransmitters. When neurons receive the threshold amount of electrical impulses or messages through dendrites they are triggered to fire and release stores of......

Words: 1510 - Pages: 7

Premium Essay


...4 Neural Conduction and Synaptic Transmission How Neurons Send and Receive Signals 4.1 4.2 4.3 ISBN 0-558-78571-9 Resting Membrane Potential Generation and Conduction of Postsynaptic Potentials Integration of Postsynaptic Potentials and Generation of Action Potentials Conduction of Action Potentials 4.5 4.6 4.7 Synaptic Transmission: Chemical Transmission of Signals among Neurons Neurotransmitters Pharmacology of Synaptic Transmission and Behavior 4.4 Biopsychology, Eighth Edition, by John P.J. Pinel. Published by Allyn & Bacon. Copyright © 2011 by Pearson Education, Inc. 76 Chapter 4 ■ Neural Conduction and Synaptic Transmission hapter 3 introduced you to the anatomy of neurons. This chapter introduces you to their function—how neurons conduct and transmit electrochemical signals through your nervous system. It begins with a description of how signals are generated in resting neurons; then, it follows the signals as they are conducted through neurons and transmitted across synapses to other neurons. It concludes with a discussion of how drugs are used to study the relation between synaptic transmission and behavior. “The Lizard,” a case study of a patient with Parkinson’s disease, Roberto Garcia d’Orta, will help you appreciate why a knowledge of neural conduction and synaptic transmission is an integral part of biopsychology. C The Lizard, a Case of Parkinson’s Disease “I have become a lizard,” he began. “A great lizard frozen in a......

Words: 14184 - Pages: 57

Free Essay

Amyotrophic Lateral Sclerosis

...know. Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease that affects nerve cells in the brain and the spinal cord. Motor neurons reach from the brain to the spinal cord and from the spinal cord to the muscles throughout the body. The progressive degeneration of the motor neurons in ALS eventually leads to their death. When the motor neurons die, the ability of the brain to initiate and control muscle movement is lost. With voluntary muscle action progressively affected, patients in the later stages of the disease may become totally paralyzed. A-myo-trophic comes from the Greek language. "A" means no or negative. "Myo" refers to muscle, and "Trophic" means nourishment–"No muscle nourishment." When a muscle has no nourishment, it "atrophies" or wastes away. "Lateral" identifies the areas in a person's spinal cord where portions of the nerve cells that signal and control the muscles are located. As this area degenerates it leads to scarring or hardening ("sclerosis") in the region. As motor neurons degenerate, they can no longer send impulses to the muscle fibers that normally result in muscle movement. Early symptoms of ALS often include increasing muscle weakness, especially involving the arms and legs, speech, swallowing or breathing. When muscles no longer receive the messages from the motor neurons that they require to function, the muscles begin to atrophy (become smaller). Limbs begin to look "thinner" as muscle tissue atrophies. ALS is......

Words: 2171 - Pages: 9

Free Essay

Mirror Neurons

...Spring 12 Mirror Neurons In Motor and Social Acts The authors who ushered in what might be considered the most critical finding of 21st century neuroscience to date—the discovery of mirror neurons (MNs)—contend that MNs underlie simulation theories of action understanding and mindreading (Gallese & Goldman, 1998); Gallese et al., (2004). The mechanism that allows mirroring of action is referred to as the ‘direct-matching hypothesis,’ (Rizzolatti et al., 2001), and the claim is based on the response properties of MNs in monkeys. The discovery of MNs is important in that if the implications of their function are properly understood, it lays a foundation for explanations of not only understanding of action and other minds (Gallese, 2003), but for other big questions, such as the evolution of language (Rizzolatti & Arbib, 1998). The concern of this paper is MN function as a feature at the core of the stronger claims. Alternative theorists challenge the characterization of the MN role as ‘mirroring’ action, as their findings show that mirroring cannot be direct and must rely on an interpretation of the observed action. They claim: a) MNs do not simulate with enough precision to be referred to as ‘mirroring,’ in which they are said to simulate an agent’s motor program onto the very same motor repertoire of an observer not performing the act; b) mirror neuron activation is predictive of action, not replicative; and c) the function of these neurons supports a model that is......

Words: 4877 - Pages: 20

Premium Essay

Mirror Nuerons

...theory in the form of mirror neurons would surely be scrutinized more than most, as the potential of such a theory has implications across many a field in psychology. However the concept of mirror neurons may have the potential to increase any understanding of how human and animal brains may function. Furthermore, in order to discuss possible implications of mirror neurons this essay has firstly presented a detailed description for the concept of mirror neurons, supporting any explanation with relevant research. In addition to any supporting research, research providing evidence to the contrary has been provided to enable a balanced analysis. Therefore, a balanced description of mirror neurons will facilitate any critical analysis for the possible psychological implications, thereby providing a balanced argument for the legitimacy of mirror neurons. Additionally, following any analysis of relevant research, a balanced and supported conclusion was produced in order to summarise any analysed research. Accordingly, the concept of mirror neurons first came to be in the winter of 1991when a paper entitled ‘Understanding motor events: A neurophysiological study’ Di Pellegrino et al (1992), the paper was originally rejected by Nature for its lack of general interest. G. Rizzolatti, M.Fabbri-Destro (2010). However, it was this paper from the University of Parma published in 1992 by the Experimental brain journal, which first showed evidence of mirror neurons in animals. G.......

Words: 2129 - Pages: 9

Premium Essay

Nervous Syste-Test

...activity of smooth and cardiac muscles and glands. NEURON STRUCTURE Neurons are nerve cells that transmit messages. The cell body of the neuron is the metabolic center of the cell and contains the nucleus. Processes extend from the cell body. In the cell body there are rough ER, Nissi substance and neurofibrils, intermediate filaments that are important in maintain cell shape and are abundant in the body. Dendrites convey messages to the cell body and axons direct nerve impulses away from the cell body. Axons end in axon terminals and the terminals contain many vesicles that contain neurotransmitters. The axon terminal is separated from the next neuron by a synaptic cleft called a synapse. Axons are covered in a myelin sheath called Schwann cells and there are breaks in the sheaths called Nodes on Ranvier. Most neurons are found in the central nervous system. There is a small collection of cell bodies outside the CNS called ganglia. The names of neurons and nerve fibers are named different in the CNS and PNS. For example a bundle of nerves in the CNS are called tracts whereas in the PNS they are called nerves. White and Gray matter refer to myelinated and unmyelinated regions of the CNS. There are three types of neurons-multipolar, bipolar and unipolar. Multipolar neurons have many extensions from the cell body. Bipolar neurons have one axon and one dendrite and unipolar neurons have a short single process leaving the process. Neurons can be classified by their functions......

Words: 1731 - Pages: 7

Premium Essay


...feet, of the neuron. Then a change occurs in the synapse, the space between the end foot and other neurons. Located near the synapse is the neuron’s terminal button, where neurotransmitters— the chemicals that are transmitted from one neuron to another— are stored in sacs.” (Psychology CH.3 pg ) The synaptic vesicles, chemical sacs located in the terminal button, makes the vesicles release neurotransmitters once electric charges from action potentials are experienced. Once neurons are released they may drift across synapse and attached to receptors sites on the postsynaptic membrane, on other sides of the synapse. If neurons are unable float into the synapse, reuptake may occur, a process by which neurons reabsorb transmitters floating freely. When a neuron is excited it is more likely to fire releasing transmitters that causes certain effects. The opposite occurs when a neuron is inhibited reducing likely chances for fire. Different types of neurotransmitters can create positive effect for some parts of the body; meanwhile affecting a different part of the body negatively, this occurs when transmitters bind both excites and inhibits neurons to certain receptor subtypes. Not all transmitters binds together and effect random parts of the body, some have a more direct effect on the neurons encounter. The attention systems cause postsynaptic neurons to fire or inhibit cells to fire. There are five different classes perform different functions related to neuron activity.......

Words: 611 - Pages: 3

Premium Essay

The Brain and Neurons Development

...The Brain and Neurons Development Developmental change evolves slowly in early childhood of the infant’s physical and central nervous systems. The infant’s physical and central nervous systems undergo rapid change during the first two years of life. The child weight double by five months of age, triples by twelve months of age, and quadruples by the age of twenty-four months. The child length does not change as fast as the weight, because the length of the child at birth is seventy-five of what it will be at the age of two years old. The changes in length and weight are accompanied by the transformations in the child’s body proportions. During this time the head grows the fastest and matures the earliest, followed by the rest of the body downward (e.g. the neck, torso, legs). Those parts that are closest to the center of the infant’s body (e.g. the trunk) grow faster and mature earliest than do parts that are farther from the center (e.g. the hands). (Santrock, 2013) The rapid changes in the child body proportions affect other domains of development, including perceptual, motor, cognitive, and emotional. The physical structure of the brain develops rapidly. We are born with almost all of the neurons that we will ever have, the human brain triples in weight by the age of three and quadruples in weight by age fourteen. The reason for the rapid change in the brain’s weight and size are first, a fatty substance called myelin forms around a part of the neuron, causing the......

Words: 599 - Pages: 3

Free Essay

Gandwun Ki Baraat

...The neurons that shaped civilizations I'd like to talk to you today about the human brain, which is what we do research on at the University of California. Just think about this problem for a second. Here is a lump of flesh, about three pounds, which you can hold in the palm of your hand. But it can contemplate the vastness of interstellar space. It can contemplate the meaning of infinity, ask questions about the meaning of its own existence, about the nature of God. 0:34And this is truly the most amazing thing in the world. It's the greatest mystery confronting human beings:How does this all come about? Well, the brain, as you know, is made up of neurons. We're looking at neurons here. There are 100 billion neurons in the adult human brain. And each neuron makes something like 1,000 to 10,000 contacts with other neurons in the brain. And based on this, people have calculatedthat the number of permutations and combinations of brain activity exceeds the number of elementary particles in the universe. 1:01So, how do you go about studying the brain? One approach is to look at patients who had lesions in different part of the brain, and study changes in their behavior. This is what I spoke about in the last TED.Today I'll talk about a different approach, which is to put electrodes in different parts of the brain, and actually record the activity of individual nerve cells in the brain. Sort of eavesdrop on the activity of nerve cells in the brain. 1:22Now, one recent......

Words: 1526 - Pages: 7

Premium Essay


...Neurons/Nerve Cells * Is the functional units of the nervous system. Parts of Neurons Cell Body- Look like a star or many legged spider with arms branching out in all directions. Dendrites- thin branches, which receive stimulation from different parts of the body and from the environments. Axon- carries nerve impulse away from the cell body. The impulse may move toward a cell body, gland or dendrites of another neurons. Myelin Sheath- a fatty substances covering the axon. 2 kinds: * Myelinated- covered axon. * Nonmyelinated- axon has no cover. Node- gap between myelin sheath Types of Neuron 1. Sensory/ Afferent- transmit information to the spinal cord and brain. 2. Motor/ Efferent- carry messages from the brain and spinal cord to the body parts causing them to react. 3. Interneuron/ Associative- carry information between two other neurons. Peripheral Nervous System * Composed of all body parts that lie outside the central nervous system. It consist: 1. Cranial Nerves- with 12 pairs of motor and sensory nerves emerge from the brain. 2. Spinal Nerves- with 31 pairs of motor and sensory comes from the spinal cord. 3. Peripheral Nerve- located outside the brain and spinal cord. Two Groups of Motor Neurons 1. Somatic Nervous System- connect the nervous system to the voluntary muscles. 2. Autonomic Nervous System- regulates the involuntary actions of glands and organs. ...

Words: 585 - Pages: 3

Premium Essay

Intro Nervous System

...system: the spinal cord, motor neurons, and sensory neurons. Sense organs in muscles transmit sensory information to spinal cord interneurons, that connect to motor neurons, that in turn activate muscles. (Adapted from Kandell et al., 2000). | | Parts of the nervous system: the spinal cord, motor neurons, and sensory neurons. Sense organs in muscles transmit sensory information to spinal cord interneurons, that connect to motor neurons, that in turn activate muscles. (Adapted from Kandell et al., 2000). | Neurons – The cellular building block of the nervous system is the neuron. These cells are typically excitable: they can “spike,” a process by which their membrane voltage quickly changes, and they transmit information. Neurons can transduce signals from the outside world into spikes, transmit spikes to each other via connections called “synapses,” and connect to muscles, in order to turn the muscle on and make it contract. When spikes happen in neurons, they may zoom along the axon (typically a long thin part of the neuron), traveling to a different part of the body. The frequencies involved in neural transmission are in the audible range – the energy of the spike is between 300 and 1000 Hz. That means after amplification we can hear the spikes of neurons, if played out of a speaker. Neurons spike due to special ion channels in their membranes. | Voltage sensitive and other ion channels are responsible for the excitability of neurons (Left). These channels......

Words: 1417 - Pages: 6

Premium Essay


...Introduction: There are two main types of cells in the brain: Neurons and neuroglia (glial cells). The neuron is the functioning unit of the nervous system; its job is to transmit impulses. There are more than 10 billion neurons in the CNS and three-fourths of them are in the cerebral cortex. Neurons are categorized in two ways; by the direction of impulse flow and by the number of process emanating from the neuronal cell’s body. Afferent sensory neurons transmit impulses to the spinal cord or brain. Efferent motor neurons transmit impulses away from the brain or spinal cord. Interneuron transmits impulses from sensory neurons to motor neurons. Neurons will be one of three types, according to the number of processes that exist which are unipolar, bipolar and multipolar. Regardless of the category of neurons, they all have certain unique structures unique to neurons which are axons, dendrites, Nissl bodies, myelin, neurilemma, and nodes of Ranvier. The neurons are highly irritable, or the ability to react to stimuli and convert them into nerve impulses, and conductivity, the ability to transmit an impulse along the cell membrane. Impulse transmission initiated by a chemical, electrical, mechanical and thermal stimulus. When a neuron is adequately stimulated, an electrical impulse is generated and conducted along the length of its axon. This response is called the action potential or nerve impulse, is always the same, and regardless of the source or type of......

Words: 1843 - Pages: 8

Premium Essay

Topic Outline

...350- to 700-word response to the following: Explain the communication process of neurons in the brain. List some common neurotransmitters and describe their effect on behavior. The communication process of neurons in the brain A brain of an average human contains approximately 100 billion nerve cells or best known as neurons. Neurons perform as information transmitters and receivers to other neurons or to muscles in the body. Neurons have these tiny fibers that extend from the body of the cell and its main function is to receive incoming messages and transmit them to the main cell. Outgoing messages to other neurons and muscles or glands are carried out by a single long fiber called the axon. Axons are covered with a white fatty tissue called myelin sheath. The myelin sheath provides insulation to avoid signals from other neurons to interfere with each other and it also increases speed when signals are been transmitted. Motor neurons carry messages from the spinal cord or the brain to the muscles and glands. Al l neurons in the nervous system only speak one language ON or OFF electrochemical impulses. The communication process of neurons in the work by impulses or what it’s also called firing. When a neuron receives a message from other neurons it automatically excites the neuron or tells the neuron to fire. This term is also known as electrochemical impulse or discharge. After the neuron has fired, it returns to a resting state and remains ready to fire......

Words: 1176 - Pages: 5

Premium Essay

The Structure of Neuron

...The Structure of a Neuron There are three basic parts of a neuron: the dendrites, the cell body and the axon. However, all neurons vary somewhat in size, shape, and characteristics depending on the function and role of the neuron. Some neurons have few dendritic branches, while others are highly branched in order to receive a great deal of information. Some neurons have short axons, while others can be quite long. The longest axon in the human body extends from the bottom of the spine to the big toe and averages a length of approximately three feet! Learn more about the structure of a neuron. Action Potentials How do neurons transmit and receive information? In order for neurons to communicate, they need to transmit information both within the neuron and from one neuron to the next. This process utilizes both electrical signals as well as chemical messengers. The dendrites of neurons receive information from sensory receptors or other neurons. This information is then passed down to the cell body and on to the axon. Once the information as arrived at the axon, it travels down the length of the axon in the form of an electrical signal known as an action potential. Communication Between Synapses Once an electrical impulse has reached the end of an axon, the information must be transmitted across the synaptic gap to the dendrites of the adjoining neuron. In some cases, the electrical signal can almost instantaneously bridge the gap between the neurons and continue along......

Words: 467 - Pages: 2