Central nervous system
Say it: SEN-trul NUR-vus SIS-tum
The central nervous system is the brain and spinal cord, the part of the nervous system that takes in sensory input, integrates it and sends out commands.
Also: CNS
Definition
What is the central nervous system?
The central nervous system, or CNS, comprises the brain and the spinal cord. It is the body's main processing center: it receives information from the senses, combines it with memory and emotion, and sends out commands to muscles and glands. Everything outside it, including the cranial and spinal nerves and their ganglia, belongs to the peripheral nervous system.
CNS tissue is divided into gray matter, rich in neuron cell bodies and dendrites, and white matter, made mostly of myelinated axons. Clusters of cell bodies inside the CNS are called nuclei, and bundles of axons are called tracts. Several kinds of glial cell work only here: oligodendrocytes make myelin, astrocytes support neurons and help form the blood-brain barrier, and microglia act as resident immune cells.
The brain sits in the skull and the spinal cord in the vertebral canal. Both are wrapped in three membranes, the meninges (dura mater, arachnoid mater and pia mater), and cushioned by cerebrospinal fluid. Strokes, infections, injuries, tumors and diseases such as multiple sclerosis can all damage the CNS.
Word parts
Where does the term “central nervous system” come from?
- centr-
- centerLatin centrum
- nerv-
- sinew, nerveLatin nervus
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Terms that go with it
- NeuronA neuron is a nerve cell, the basic signaling unit of the nervous system, which receives information and passes it on as electrical and chemical signals.
- Autonomic nervous systemThe autonomic nervous system is the division of the nervous system that runs involuntary functions such as heart rate, digestion and gland secretion.
- MyelinMyelin is the fatty, layered sheath that glial cells wrap around many axons, insulating them so nerve impulses travel faster and more efficiently.
- SynapseA synapse is the junction where a neuron passes a signal to another cell, usually by releasing a neurotransmitter across a narrow gap.
- StrokeA stroke is a sudden loss of brain function that happens when an artery supplying the brain is blocked or bursts and bleeds.
- EpilepsyEpilepsy is a long-term brain disorder in which a person has repeated unprovoked seizures caused by bursts of abnormal electrical activity in neurons.
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Written for biofideX in plain words, after checking these references:
- OpenStax Anatomy and Physiology 2e, 12.1 Basic Structure and Function of the Nervous System
- OpenStax Biology 2e, 35.3 The Central Nervous System
- NCI Dictionary of Cancer Terms: central nervous system
- NCBI MeSH: Central Nervous System
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