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 parasympathetic nervous system does the exact opposite: It prepares the body for rest.
It also helps the digestive tract move along so our bodies can efficiently take in nutrients from the food we eat. Sight probably tells us more about the world than any other sense.
Light entering the eye forms an upside-down image on the retina. The retina transforms the light into nerve signals for the brain.
The electrical signal then travels through the neuron and goes through the same conversion processes as it moves to neighboring neurons. The nervous system also includes non-neuron cells, called glia pronounced GLEE-uh. Glia perform many important functions that keep the nervous system working properly. For example, glia:. The brain is made up of many networks of communicating neurons and glia. The nervous system has two main parts: The central nervous system is made up of the brain and spinal cord.
The State of Victoria and the Department of Health shall not bear any liability for reliance by any user on the materials contained on this website. Skip to main content. Brain and nerves. Home Brain and nerves. Nervous system. Actions for this page Listen Print. Summary Read the full fact sheet. On this page. Neurones are the building blocks Central nervous system The peripheral nervous system Problems of the nervous system Where to get help Things to remember. Neurones are the building blocks The basic building block of the nervous system is a nerve cell, or neurone.
Central nervous system The brain and the spinal cord make up the central nervous system. The spinal cord The spinal cord is connected to the brain and runs the length of the body. The peripheral nervous system Nerves connect the brain and spinal cord to the peripheral nervous system, which is what nerve tissue outside of the central nervous system is called. The autonomic nervous system The autonomic nervous system is part of the peripheral nervous system.
The somatic nervous system The somatic nervous system is also a part of the peripheral nervous system. Symptoms include shaking and problems with movement Sciatica — pressure on a nerve caused by a slipped disc in the spine or arthritis of the spine and, sometimes, other factors Shingles — infection of sensory nerves caused by the varicella-zoster virus Stroke — a lack of blood to part of the brain.
Where to get help Your doctor Things to remember The nervous system uses electrical and chemical means to help all parts of the body to communicate with each other.
The spinal cord, running almost the full length of the back, carries information between the brain and body, but also carries out other tasks. Along its length, it connects with the nerves of the peripheral nervous system PNS that run in from the skin, muscles, and joints.
Motor commands from the brain travel from the spine to the muscles and sensory information travels from the sensory tissues — such as the skin — toward the spinal cord and finally up to the brain. The spinal cord contains circuits that control certain reflexive responses, such as the involuntary movement your arm might make if your finger was to touch a flame. The circuits within the spine can also generate more complex movements such as walking.
Even without input from the brain, the spinal nerves can coordinate all of the muscles necessary to walk. For instance, if the brain of a cat is separated from its spine so that its brain has no contact with its body, it will start spontaneously walking when placed on a treadmill.
The brain is only required to stop and start the process, or make changes if, for instance, an object appears in your path. The CNS can be roughly divided into white and gray matter. As a very general rule, the brain consists of an outer cortex of gray matter and an inner area housing tracts of white matter. Both types of tissue contain glial cells, which protect and support neurons.
White matter mostly consists of axons nerve projections and oligodendrocytes — a type of glial cell — whereas gray matter consists predominantly of neurons. Also called neuroglia, glial cells are often called support cells for neurons. In the brain, they outnumber nerve cells 10 to 1. Without glial cells, developing nerves often lose their way and struggle to form functioning synapses.
The following are brief descriptions of the CNS glial cell types:. Astrocytes: these cells have numerous projections and anchor neurons to their blood supply.
They also regulate the local environment by removing excess ions and recycling neurotransmitters. Oligodendrocytes: responsible for creating the myelin sheath — this thin layer coats nerve cells, allowing them to send signals quickly and efficiently.
The cranial nerves are 12 pairs of nerves that arise directly from the brain and pass through holes in the skull rather than traveling along the spinal cord. These nerves collect and send information between the brain and parts of the body — mostly the neck and head. Of these 12 pairs, the olfactory and optic nerves arise from the forebrain and are considered part of the central nervous system:.
Olfactory nerves cranial nerve I : transmit information about odors from the upper section of the nasal cavity to the olfactory bulbs on the base of the brain. Optic nerves cranial nerve II : carry visual information from the retina to the primary visual nuclei of the brain.
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