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Somatic nervous system | |
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![]() 1. (Brain) Precentral gyrus: the origin of nerve signals initiating movement.
2. (Cross section of Spinal cord) Corticospinal tract: Mediator of message from brain to skeletal muscles. 3. Axon: the efferent nerve fiber that carries the command to contract muscles. 4. Neuromuscular junction: muscle cells are stimulated to contract at this intersection | |
Details | |
Synonym | Voluntary nervous system |
Part of | Peripheral nervous system |
Identifiers | |
FMA | 9904 |
Anatomical terminology |
The somatic nervous system (SNS), also known as voluntary nervous system, is a part of the peripheral nervous system (PNS) that links brain and spinal cord to skeletal muscles under conscious control, as well as to sensory receptors in the skin.[1][2] The other part complementary to the somatic nervous system is the autonomic nervous system (ANS).
The somatic nervous system consists of nerves carrying afferent nerve fibers, which relay sensation from the body to the central nervous system (CNS), and nerves carrying efferent nerve fibers, which relay motor commands from the CNS to stimulate muscle contraction.[3] Specialized nerve fiber ends called sensory receptors are responsible for detecting information both inside and outside the body.
The a- of afferent and the e- of efferent correspond to the prefixes ad- (to, toward) and ex- (out of).