Central Nervous System

Central Nervous System
From Wikipedia, the free encyclopedia

A diagram showing the CNS:
1. Brain
2. Central nervous system (brain and spinal cord)
3. Spinal cord

The central nervous system (CNS) represents the largest part of the nervous system, including the brain and the spinal cord. Together with the Peripheral Nervous System , it has a fundamental role in the control of behavior. The CNS is contained within the dorsal cavity, with the brain within the cranial cavity, and the spinal cord in the spinal cavity. The CNS is covered by the meninges. The brain is also protected by the skull, and the spinal cord is also protected by the vertebrae. [1]

Function
Main article: Brain Function
Since the strong theoretical influence of cybernetics in the fifties, the central nervous system is conceived as a system devoted to information processing, where an appropriate motor output is computed as a response to a sensory input. Yet, many threads of research suggest that motor activity exists well before the maturation of the sensory systems and then, that the senses only influence behaviour without dictating it. This has brought the conception of the CNS as an autonomous system.

Development
Main article: Neural development
In the developing fetus, the CNS originates from the neural plate, a specialised region of the ectoderm, the most external of the three embryonic layers. During embryonic development, the neural plate folds and forms the neural tube. The internal cavity of the neural tube will give rise to the ventricular system. The regions of the neural tube will differentiate progressively into transversal systems. First, the whole neural tube will differentiate into its two major subdivisions: brain (rostral/cephalic) and spinal cord (caudal). Consecutively, the brain will differentiate into prosencephalon and brainstem. Later, the prosencephalon will subdivide into telencephalon and diencephalon, and the brainstem into mesencephalon and rhombencephalon.

Neuroanatomy
Main article: Neuroanatomy
The telencephalon gives rise to the striatum (caudate nucleus and putamen), the hippocampus and the neocortex, its cavity becomes the lateral ventricles (first and second ventricles). The diencephalon give rise to the subthalamus, hypothalamus, thalamus and epithalamus, its cavity to the third ventricle. The mesencephalon gives rise to the tectum, pretectum, cerebral peduncle and its cavity develops into the mesencephalic duct or cerebral aqueduct. Finally, the rhombencephalon gives rise to the pons, the cerebellum and the medulla oblongata, its cavity becomes the fourth ventricle.
Centralnervoussystem
I Brain
A Prosencephalon
1. Telencephalon
2. Rhinencephalon,
3. Amygdala,
4. Hippocampus,
5. Neocortex,
6. Lateral ventricles
B Diencephalon
1. Epithalamus,
2. Thalamus, Hypothalamus, Subthalamus, Pituitary gland, Pineal gland, Third ventricle
Brain stem
Mesencephalon
Tectum, Cerebral peduncle, Pretectum, Mesencephalic duct
Rhombencephalon
Metencephalon
Pons, Cerebellum,
Myelencephalon
Medulla oblongata
Spinal cord

Evolution
Main article: Brain
The basic pattern of the CNS is highly conserved throughout the different species of vertebrates and during evolution. The major trend that can be observed is towards a progressive telencephalisation: while in the reptilian brain that region is only an appendix to the large olfactory bulb, it represents most of the volume of the mammalian CNS. In the human brain, the telencephalon covers most of the diencephalon and the mesencephalon. Indeed, the allometric study of brain size among different species shows a striking continuity from rats to whales, and allows us to complete the knowledge about the evolution of the CNS obtained through cranial endocasts.See also: Encephalization, Neocortex, Archicortex

Parts of the vertebrate CNS
Main article: List of regions in the human brain
In addition to the structures seen to the right in table above, a vast number of structures are present in the adult brain.

See also
Glossary of anatomical terminology, definitions and abbreviations
List of regions in the human brain
Central nervous system infection
Neuroradiology

References
^ Maton, Anthea; Jean Hopkins, Charles William McLaughlin, Susan Johnson, Maryanna Quon Warner, David LaHart, Jill D. Wright (1993). Human Biology and Health. Englewood Cliffs, New Jersey, USA: Prentice Hall, 132-144. ISBN 0-13-981176-1.

External links
Sylvius: 400+ structure neuroanatomical visual glossary
High-Resolution Cytoarchitectural Primate Brain Atlases
Human Brains: A Learning Tool.
Explaining the human nervous system.
Nervous System - Back Pain - Anatomy (info on nerve pairs).
Textbook in Medical Physiology And Pathophysiology, many links
Brain and Cranial Nerves, Anatomy and Physiology Lecture, Northland Community College
Latest Research on the Brain and Central Nervous System From ScienceDaily
[show]
v • d • eNervous system
Central nervous system
Brain • Spinal cord
Autonomic nervous system
Sympathetic • Parasympathetic
Other
Peripheral nervous system • Somatic nervous system • Enteric nervous system • Sensory system
[show]
v • d • eHistology: nervous tissue
Neurons (gray matter)
soma, axon (axon hillock, axoplasm, axolemma, neurofibril/neurofilament), dendrite (Nissl body, dendritic spine, apical dendrite, basal dendrite)types (bipolar, pseudounipolar, multipolar, pyramidal, Purkinje, granule)
Afferent nerve/Sensory nerve/Sensory neuron
GSA, GVA, SSA, SVA, fibers (Ia, Ib or Golgi, II or Aβ, III or Aδ or fast pain, IV or C or slow pain)
Efferent nerve/Motor nerve/Motor neuron
GSE, GVE, SVE, Upper motor neuron, Lower motor neuron (α motorneuron, γ motorneuron)
Synapses
neuropil, synaptic vesicle, neuromuscular junction, electrical synapse - Interneuron (Renshaw)
Sensory receptors
Free nerve ending, Meissner's corpuscle, Merkel nerve ending, Muscle spindle, Pacinian corpuscle, Ruffini ending, Olfactory receptor neuron, Photoreceptor cell, Hair cell, Taste bud
Glial cells
astrocyte, oligodendrocyte, ependymal cells, microglia, radial glia
Myelination (white matter)
Schwann cell, oligodendrocyte, nodes of Ranvier, internode, Schmidt-Lanterman incisures, neurolemma
Related connective tissues
epineurium, perineurium, endoneurium, nerve fascicle, meninges
Retrieved from "http://en.wikipedia.org/wiki/Central_nervous_system"
Categories: Neurology Nervous system Central nervous system

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