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( Neuron)
Neurons (IPA /'nju???n/, also known as neurones and nervous cells) are responsive cells in the nervous system that process and transmit information by chemical signals within the neuron. They are the core components of the brain, the vertebrate spinal cord, the invertebrate ventral nerve cord, and the peripheral nerves. A number of different types of neurons exist sensory neurons respond to touch, sound, light and numerous other stimuli affecting cells of the sensory organs that then send signals to the spinal cord and brain. Motor neurons receive signals from the brain and spinal cord and cause muscle contractions and affect glands. Inter-neurons connect neurons to other neurons within the brain and spinal cord. Neurons respond to stimuli, and communicate the presence of stimuli to the central nervous system, which processes that information and sends responses to other parts of the body for action. The complexity and diversity in nervous systems is dependent on the interconnections between neurons, which rely on a limited number of different signals transmitted within the neurons to other neurons or to muscles and glands. The signals are produced and propagated by chemical ions that produce an electrical charge that moves along the neuron. Neurons exist in a number of different shapes and sizes and can be classified by their morphology and function. The anatomist Camillo Golgi grouped neurons into two types; type I with long axons used to move signals over long distances and type II without axons. type I cells can be further divided by where the cell body or soma is located. The basic morphology of type I neurons, represented by spinal motor neurons, consists of a cell body called the soma, a long thin axon which is covered by the myelin sheath. Around the cell body is a branching dendritic tree that receives signals from other neurons, the end of the axon has branching terminals (axon terminal) that release transmitter secretions into an area called the gap junction between the terminals and the dendrites of next neuron. The anatomy and the properties of the surface membrane determine the behavior of a neuron. The surface membrane is not uniform over the entire length of a neuron, but is modified in specific areas, some regions secrete transmitter substances while other areas respond to transmitter molecules. Other areas of the neuron membrane have passive electrical properties that effect capacitance and resistance. Within the neuron membrane there are gated ion channels that vary in type, the membrane of the axons include fast response sodium channels that are voltage-gated and are used to send rapid signals. Neurons communicate by chemical and electrical synapses, in a process known as synaptic transmission. The fundamental process that triggers synaptic transmission is the action potential, a propagating electrical signal that is generated by exploiting the electrically excitable membrane of the neuron. This is also known as a wave of depolarization.
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Neuron Subcategories
Neuron Articles
Detailed Information on Motor Neuron Disease by Juliet Cohen
Motor neurone disease is one of the most frequent neurodegenerative diseases of adult onset. Motor neurone disease is a advanced, degenerative disorder that affects nerves in the upper or lower parts of the body. Upper motor neurons direct the lower ...
Cocktails, Neurons and Nanos: Super-Cognition? by Pedro Gondim
Improving overall cognitive capability is becoming as simple as consuming a pill... An interesting paradox has been the axis of much attention in the fields of pharmacy, brain research and ethics in the last few years. The advent of ne...
A role of melanin-concentrating hormone producing neurons in the central regulation of paradoxical sleep
A role of melanin-concentrating hormone producing neurons in the central regulation of paradoxical sleep
Laure Verret* , Romain Goutagny* , Patrice Fort , Laurène Cagnon , Denise Salvert , Lucienne Léger ...
Leptin and insulin stimulation of signalling pathways in arcuate nucleus neurones: PI3K dependent actin reorganization and KATP channel act
Leptin and insulin stimulation of signalling pathways in arcuate nucleus neurones: PI3K dependent actin reorganization and KATP channel activation
Shirin Mirshamsi1 , Hilary A Laidlaw1 , Ke Ning1 , Erin An...
The role of Serine Proteases and Serine Protease Inhibitors in the migration of Gonadotropin-Releasing Hormone neurons
The role of Serine Proteases and Serine Protease Inhibitors in the migration of Gonadotropin-Releasing Hormone neurons
Paola T Drapkin1 , Denis Monard2 and Ann-Judith Silverman3 1Uni...
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