Sistema nervioso somático: Diferenzas entre revisións
traducido de en:Somatic nervous system |
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==Partes do sistema nervioso somático== |
==Partes do sistema nervioso somático== |
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No noso corpo existen 43 segmentos de [[nervio]]s e en cada segmento hai un par de nervios motores e sensoriais. No corpo, 31 segmentos de nervios están na [[medula espiñal]] e 12 no [[tronco cerebral]]. Ademais destes, no corpo existen miles de nervios de asociación. |
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There are forty three segments of nerves in our body and with each segment there is a pair of sensory and motor nerves. In the body, thirty one segments of nerves are in the spinal cord and twelve are in the brain stem. |
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Deste modo, o sistema nervioso somático consta de tres partes: |
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Besides these, thousands of association nerves are also present in the body. |
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i) '''Nervios espiñais ou raquídeos:''' Son nervios periféricos que levan información sensorial á medula espiñal e ordes motoras. |
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Thus Somatic Nervous System consists of three parts: |
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ii) '''Nervios craniais:''' Son fibras nerviosas que levan información cara adentro e fóra do tronco cerebral. Inclúen os encargados do olfacto, visión, ollo, músculos do ollo, boca, gusto, oído, pescozo, ombros e lingua. |
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i) '''Spinal Nerves:''' They are peripheral nerves that carry sensory information into the spinal cord and motor commands. |
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iii) '''Nervios de asociación:''' Estes nervios integran as entradas sensoriais e as saídas motoras. |
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ii) '''Cranial Nerves:''' They are the nerve fibers which carry information into and out of the brain stem. They include smell, vision, eye, eye muscles, mouth, taste, ear, neck, shoulders and tongue. |
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iii) '''Association Nerves:''' These nerves integrate sensory input and motor output numbering thousands. |
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==Transmisión de sinais nerviosos== |
==Transmisión de sinais nerviosos== |
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Revisión como estaba o 6 de febreiro de 2014 ás 18:01
 | Este artigo está a ser traducido ao galego por un usuario desta Wikipedia; por favor, non o edite. O usuario Miguelferig (conversa · contribucións) realizou a última edición na páxina hai 10 anos. Se o usuario non publica a tradución nun prazo de trinta días, procederase ó seu borrado rápido. |
O sistema nervioso somático ou sistema nervioso voluntario é a parte do sistema nervioso periférico [1] asociada co control voluntario dos movementos do corpo por medio dos músculos esqueléticos. O sistema nervioso somático consta de nervios eferentes responsables da estimulación da contracción muscular, e inclúe todas as neuronas non sensoriais conectadas cos músculos esqueléticos e a pel.
Partes do sistema nervioso somático
No noso corpo existen 43 segmentos de nervios e en cada segmento hai un par de nervios motores e sensoriais. No corpo, 31 segmentos de nervios están na medula espiñal e 12 no tronco cerebral. Ademais destes, no corpo existen miles de nervios de asociación.
Deste modo, o sistema nervioso somático consta de tres partes:
i) Nervios espiñais ou raquídeos: Son nervios periféricos que levan información sensorial á medula espiñal e ordes motoras.
ii) Nervios craniais: Son fibras nerviosas que levan información cara adentro e fóra do tronco cerebral. Inclúen os encargados do olfacto, visión, ollo, músculos do ollo, boca, gusto, oído, pescozo, ombros e lingua.
iii) Nervios de asociación: Estes nervios integran as entradas sensoriais e as saídas motoras.
Transmisión de sinais nerviosos
The somatic nervous system controls all voluntary muscular systems within the body, with the exception of reflex arcs.
The basic route of nerve signals within the efferent somatic nervous system involves a sequence that begins in the upper cell bodies of motor neurons (upper motor neurons) within the precentral gyrus (which approximates the primary motor cortex). Stimuli from the precentral gyrus are transmitted from upper motor neurons and down the corticospinal tract, via axons to control skeletal (voluntary) muscles. These stimuli are conveyed from upper motor neurons through the ventral horn of the spinal cord, and across synapses to be received by the sensory receptors of alpha motor neurons (large lower motor neurons) of the brainstem and spinal cord.
Upper motor neurons release a neurotransmitter, acetylcholine, from their axon terminal knobs, which are received by nicotinic receptors of the alpha motor neurons. In turn, alpha motor neurons relay the stimulus.
From there, acetylcholine is released from the axon terminal knobs of alpha motor neurons and received by postsynaptic receptors (Nicotinic acetylcholine receptors) of muscles, thereby relaying the stimulus to contract muscle fibers.
Diferenzas en vertebrados e invertebrados
In invertebrates, depending on the neurotransmitter released and the type of receptor it binds, the response in the muscle fiber could either be excitatory or inhibitory. For vertebrates, however, the response of a muscle fiber to a neurotransmitter (always acetylcholine (ACh)) can only be excitatory.
Arcos reflexos
A reflex arc is a neural circuit that creates a more or less automatic link between a sensory input and a specific motor output. Reflex circuits vary in complexity—the simplest spinal reflexes are mediated by a three-element chain, beginning with sensory neurons which activate interneurons in the spinal cord, which then activate motor neurons. Some reflex responses, such as withdrawing the hand after touching a hot surface, are protective, but others, such as the patellar reflex "knee jerk" activated by tapping the patellar tendon, contribute to ordinary behaviour.