Because it regulates every process in the body. Explanation: The nervous system is the complete network of nerve cells neurons. Related questions The central nervous system and the peripheral nervous system differ in the way the nerves All nervous tissue outside of the central nervous system is part of what nervous system?
How are the somatic and autonomic nervous systems similar? Which spinal segments have gray communicants? Which have white rami? What is the control center of the parasympathetic nervous system? For example, sensory neurons send information from the eyes, ears, nose, tongue, and skin to the brain.
Motor neurons carry messages away from the brain to the rest of the body. All neurons, however, relay information to each other through a complex electrochemical process, making connections that affect the way we think, learn, move, and behave. Intelligence, learning, and memory. As we grow and learn, messages travel from one neuron to another over and over, creating connections, or pathways, in the brain. It's why driving takes so much concentration when someone first learns it, but later is second nature: The pathway became established.
In young children, the brain is highly adaptable. In fact, when one part of a young child's brain is injured, another part often can learn to take over some of the lost function. But as we age, the brain has to work harder to make new neural pathways, making it harder to master new tasks or change set behavior patterns. That's why many scientists believe it's important to keep challenging the brain to learn new things and make new connections — it helps keeps the brain active over the course of a lifetime.
Memory is another complex function of the brain. The things we've done, learned, and seen are first processed in the cortex. Then, if we sense that this information is important enough to remember permanently, it's passed inward to other regions of the brain such as the hippocampus and amygdala for long-term storage and retrieval. As these messages travel through the brain, they too create pathways that serve as the basis of memory.
Different parts of the cerebrum move different body parts. The left side of the brain controls the movements of the right side of the body, and the right side of the brain controls the movements of the left side of the body. When you press your car's accelerator with your right foot, for example, it's the left side of your brain that sends the message allowing you to do it. Basic body functions. A part of the peripheral nervous system called the autonomic nervous system controls many of the body processes we almost never need to think about, like breathing, digestion, sweating, and shivering.
The autonomic nervous system has two parts: the sympathetic nervous system and the parasympathetic nervous system. The sympathetic nervous system prepares the body for sudden stress, like if you witness a robbery. When something frightening happens, the sympathetic nervous system makes the heart beat faster so that it sends blood quickly to the different body parts that might need it.
It also causes the adrenal glands at the top of the kidneys to release adrenaline, a hormone that helps give extra power to the muscles for a quick getaway. This process is known as the body's "fight or flight" response. The cell bodies of somatic sensory neurons lie in dorsal root ganglion of the spinal cord.
The visceral part, also known as the autonomic nervous system, contains neurons that innervate the internal organs, blood vessels, and glands. The autonomic nervous system itself consists of two parts: the sympathetic nervous system and the parasympathetic nervous system. Some authors also include sensory neurons whose cell bodies lie in the periphery for senses such as hearing as part of the PNS; others, however, omit them Hubbard, , p.
The vertebrate nervous system can also be divided into areas called gray matter "grey matter" in British spelling and white matter. Gray matter which is only gray in preserved tissue, and is better described as pink or light brown in living tissue contains a high proportion of cell bodies of neurons. White matter is composed mainly of myelin-coated axons, and takes its color from the myelin. White matter includes all of the body's nerves, and much of the interior of the brain and spinal cord.
Gray matter is found in clusters of neurons in the brain and spinal cord, and in cortical layers that line their surfaces. There is an anatomical convention that a cluster of neurons in the brain is called a "nucleus", whereas a cluster of neurons in the periphery is called a "ganglion".
There are, however, a few exceptions to this rule, notably the part of the brain called the basal ganglia. Sponges have no cells connected to each other by synaptic junctions, that is, no neurons, and therefore no nervous system.
They do, however, have homologs of many genes that play key roles in synaptic function in other animals. Recent studies have shown that sponge cells express a group of proteins that cluster together to form a structure resembling a postsynaptic density the signal-receiving part of a synapse Sakarya, However, the function of that structure is currently unclear.
Although sponge cells do not show synaptic transmission, they do communicate with each other via calcium waves and other impulses, which mediate some simple actions such as whole-body contraction Jacobs et al.
Jellyfish, comb jellies, and related animals have diffuse nerve nets rather than a central nervous system. In most jellyfish the nerve net is spread more or less evenly across the body; in comb jellies it is concentrated near the mouth. The nerve nets consist of sensory neurons, which pick up chemical, tactile, and visual signals; motor neurons, which can activate contractions of the body wall; and intermediate neurons, which detect patterns of activity in the sensory neurons and, in response, send signals to groups of motor neurons.
In some cases groups of intermediate neurons are clustered into discrete ganglia Ruppert et al. The development of the nervous system in radiata is relatively unstructured. Unlike bilaterians, radiata only have two primordial cell layers, the endoderm and ectoderm.
Neurons are generated from a special set of ectodermal precursor cells, which also serve as precursors for every other ectodermal cell type Sanes et al.
The vast majority of existing animals are bilaterians, meaning animals with left and right sides that are approximate mirror images of each other. All bilateria are thought to have descended from a common wormlike ancestor that appeared during the Cambrian period, — million years ago Balavoine, The fundamental bilaterian body form is a tube with a hollow gut cavity running from mouth to anus, and a nerve cord or two parallel nerve cords , with an enlargement a "ganglion" for each body segment, with an especially large ganglion at the front, called the "brain".
It has not been definitively established whether the generic form of the bilaterian central nervous system is inherited from the so-called "Urbilaterian" — the last common ancestor of all existing bilaterians — or whether separate lines have evolved similar structures in parallel Northcutt, On one hand, the presence of a shared set of genetic markers, as well as a tripartite brain structure shared by widely separated species Hirth, , suggest common derivation; on the other hand, the fact that some modern types of bilaterians such as echinoderms lack a central nerve cord, while many lack recognizably tripartite brains, suggest that this might have been the primitive state Northcutt, Vertebrates, annelids, crustaceans, and insects all show the segmented bilaterian body plan at the level of the nervous system.
In mammals, the spinal cord contains a series of segmental ganglia, each giving rise to motor and sensory nerves that innervate a portion of the body surface and underlying musculature. On the limbs, the layout of the innervation pattern is complex, but on the trunk it gives rise to a series of narrow bands.
The top three segments belong to the brain, giving rise to the forebrain, midbrain, and hindbrain Ghysen, Bilaterians can be divided, based on events that occur very early in embryonic development, into two groups superphyla called protostomes and deuterostomes Erwin et al.
Deuterostomes include vertebrates as well as echinoderms, hemichordates mainly acorn worms , and Xenoturbellidans Bourlat et al. Protostomes, the more diverse group, include arthropods, molluscs, and numerous types of worms. There is a basic difference between the two groups in the placement of the nervous system within the body: protostomes possess a nerve cord on the ventral usually bottom side of the body, whereas in deuterostomes the nerve cord is on the dorsal usually top side.
In fact, numerous aspects of the body are inverted between the two groups, including the expression patterns of several genes that show dorsal-to-ventral gradients. Most anatomists now consider that the bodies of protostomes and deuterostomes are "flipped over" with respect to each other, a hypothesis that was first proposed by Geoffroy Saint-Hilaire for insects in comparison to vertebrates.
Thus insects, for example, have nerve cords that run along the ventral midline of the body, while all vertebrates have spinal cords that run along the dorsal midline Lichtneckert and Reichert, Worms are the simplest bilaterian animals, and reveal the basic structure of the bilaterian nervous system in the most straightforward way. As an example, earthworms have dual nerve cords running along the length of the body and merging at the tail and the mouth.
These nerve cords are connected to each other by transverse nerves resembling the rungs of a ladder. These transverse nerves help coordinate movement of the two sides of the animal. Two ganglia at the head end function as a simple brain. Photoreceptors in the animal's eyespots provide sensory information on light and dark Adey, WR. The nervous system of one particular type of nematode, the tiny roundworm Caenorhabditis elegans , has been mapped out down to the synaptic level.
This has been possible because in this species, every individual worm ignoring mutations and sex differences has an identical set of neurons, with the same locations and chemical features, and the same connections to other cells. Every neuron and its cellular lineage has been recorded and most, if not all, of the neural connections are mapped.
The nervous system of C. Males have exactly neurons, while hermaphrodites have exactly neurons Hobert, , an unusual feature called eutely. Arthropods, such as insects and crustaceans, have a nervous system made up of a series of ganglia, connected by a pair of ventral nerve cords running along the length of the abdomen Chapman, Most body segments have one ganglion on each side, but some are fused to form the brain and other large ganglia.
The head segment contains the brain, also known as the supraesophageal ganglion. In the insect nervous system, the brain is anatomically divided into the protocerebrum, deutocerebrum, and tritocerebrum. Immediately behind the brain is the subesophageal ganglion, which is composed of three pairs of fused ganglia. It controls the mouthparts, the salivary glands and certain muscles.
Many arthropods have well-developed sensory organs, including compound eyes for vision and antennae for olfaction and pheromone sensation. The sensory information from these organs is processed by the brain. These systems act on the body in opposite ways. Together, they coordinate a multitude of adjustments required for our changing personal needs as we move through our environment.
For example, the size of our pupils is adjusted automatically to allow the correct amount of light into our eyes for optimum vision, our sweat glands are turned on when we get too hot and our salivary glands produce saliva when we eat food or even think about it! The somatic nervous system is also a part of the peripheral nervous system. One of its roles is to relay information from the eyes, ears, skin and muscle to the central nervous system brain and spinal cord.
It also obeys commands from the central nervous system and makes muscles contract or relax, allowing us to move. This page has been produced in consultation with and approved by:. The long-term effects of brain injury will be different for each person and can range from mild to profound. A person with alcohol related brain impairment ARBI might experience problems with coordination, thinking, planning and memory. If a person with alcohol related brain impairment is aware of their memory limits, they can learn how to deal with them.
People with alcohol related brain impairment benefit when their life is organised and follows a good structure. Loss of memory can be temporary or permanent, but 'amnesia' usually refers to the temporary variety.
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