peripheral nervous system

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peripheral nervous system

anatomy

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July 1, 2026

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The peripheral nervous system (PNS) acts as a communication network, transmitting sensory and motor signals between the central nervous system and the rest of the body. It comprises spinal nerves, cranial nerves, and parts of the autonomic nervous system. These pathways are made of neurons, with cell bodies often grouped in clusters called ganglia. Spinal nerves, formed by dorsal and ventral roots, are the primary structural and functional units of the PNS. These nerves are classified as mixed, containing both sensory (afferent) and motor (efferent) fibers that carry information to and from the body's surface, muscles, and internal organs.123

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human nervous system
The peripheral nervous system
The peripheral nervous system is a channel for the relay of sensory and motor impulses between the central nervous system on one hand and the body surface, skeletal muscles, and internal organs on the other hand. It is composed of (1) spinal…
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The peripheral nervous system is a channel for the relay of sensory and motor impulses between the central nervous system on one hand and the body surface, skeletal muscles, and internal organs on the other hand. It is composed of (1) spinal…
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Guillain-Barré syndrome
Pathophysiology
…closely resembles a constituent of peripheral nerve cells. The high degree of similarity confuses the immune system and thereby triggers an immune response against both the infectious agent and the peripheral nerve cells. The inadvertent immune attack on the body’s own nerve tissues results in nerve inflammation and demyelination, or…
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…closely resembles a constituent of peripheral nerve cells. The high degree of similarity confuses the immune system and thereby triggers an immune response against both the infectious agent and the peripheral nerve cells. The inadvertent immune attack on the body’s own nerve tissues results in nerve inflammation and demyelination, or…
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Schwann cell
…of the cells in the peripheral nervous system that produce the myelin sheath around neuronal axons. Schwann cells are named after German physiologist Theodor Schwann, who discovered them in the 19th century. These cells are equivalent to a type of neuroglia called
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…of the cells in the peripheral nervous system that produce the myelin sheath around neuronal axons. Schwann cells are named after German physiologist Theodor Schwann, who discovered them in the 19th century. These cells are equivalent to a type of neuroglia called
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human nervous system
Peripheral nerves
Most of the afferent nerves making up the dorsal roots are nonmyelinated fibers. These fibers are activated by warmth within a physiological range (and by higher temperatures likely to damage the body), by chemical substances (including those produced by the body), and by…
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Most of the afferent nerves making up the dorsal roots are nonmyelinated fibers. These fibers are activated by warmth within a physiological range (and by higher temperatures likely to damage the body), by chemical substances (including those produced by the body), and by…
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nervous system
The vertebrate system
… and spinal cord, and the peripheral nervous system, which in humans includes 12 pairs of cranial nerves, 31 pairs of spinal nerves, and the autonomic, or involuntary, nervous system.
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… and spinal cord, and the peripheral nervous system, which in humans includes 12 pairs of cranial nerves, 31 pairs of spinal nerves, and the autonomic, or involuntary, nervous system.
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