When we move, the brain sends a message to the spinal cord. From there, the nerves carry the message to the necessary muscles to make them contract and produce movement. Similarly, when we touch an object, sensory information is carried through the nerves to the spinal cord and then to the brain so we can make sense of that information. Peripheral nerve disorders distort or interrupt messages sent between the brain and the rest of the body.
This can result in:. These two components cooperate at all times to ensure our lively functions: we are nothing without our nervous system! Unlike the brain and the spinal cord of the central nervous system that are protected by the vertebrae and the skull, the nerves and cells of the peripheral nervous system are not enclosed by bones, and therefore are more susceptible to trauma.
If we consider the entire nervous system as an electric grid, the central nervous system would represent the powerhouse, whereas the peripheral nervous system would represent long cables that connect the powerhouse to the outlying cities limbs, glands and organs to bring them electricity and send information back about their status.
Image credit: Alessandra Donato. Basically, signals from the brain and spinal cord are relayed to the periphery by motor nerves, to tell the body to move or to conduct resting functions like breathing, salivating and digesting , for example. The peripheral nervous system sends back the status report to the brain by relaying information via sensory nerves see above image. As with the central nervous system, the basic cell units of the peripheral central nervous system are neurons.
Each neuron has a long process, known as the axon, which transmits the electrochemical signals through which neurons communicate. Axons of the peripheral nervous system run together in bundles called fibres , and multiple fibres form the nerve , the cable of the electric circuit. Measure content performance. Develop and improve products. List of Partners vendors. What exactly is the peripheral nervous system and what role does it play in the body?
First, it is important to realize that the nervous system is divided into two parts: the central nervous system and the peripheral nervous system. The central nervous system includes the brain and spinal cord, while the peripheral nervous system includes all of the nerves that branch out from the brain and spinal cord and extend to other parts of the body including muscles and organs. Each part of the system plays a vital role in how information is communicated throughout the body. The peripheral nervous system PNS is the division of the nervous system containing all the nerves that lie outside of the central nervous system CNS.
These nerves extend from the central nervous system to the outermost areas of the body. The peripheral system allows the brain and spinal cord to receive and send information to other areas of the body, which allows us to react to stimuli in our environment. The nerves that make up the peripheral nervous system are actually the axons or bundles of axons from nerve cells or neurons. In some cases, these nerves are very small but some nerve bundles are so large that they can be easily seen by the human eye.
The peripheral nervous system itself is divided into two parts: the somatic nervous system and the autonomic nervous system. Each of these components plays a critical role in how the peripheral nervous system operates. The somatic system is the part of the peripheral nervous system responsible for carrying sensory and motor information to and from the central nervous system.
A nerve may also have blood vessels enclosed in its connective tissue wrappings. Twelve pairs of cranial nerves emerge from the inferior surface of the brain. All of these nerves, except the vagus nerve , pass through foramina of the skull to innervate structures in the head , neck , and facial region.
The cranial nerves are designated both by name and by Roman numerals, according to the order in which they appear on the inferior surface of the brain. Most of the nerves have both sensory and motor components. Three of the nerves are associated with the special senses of smell , vision, hearing , and equilibrium and have only sensory fibers. Five other nerves are primarily motor in function but do have some sensory fibers for proprioception.
The remaining four nerves consist of significant amounts of both sensory and motor fibers. Acoustic neuromas are benign fibrous growths that arise from the balance nerve, also called the eighth cranial nerve or vestibulocochlear nerve.
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