Everything about The Central Nervous System totally explained
The
central nervous system (
CNS) of the
vertebrate nervous system which is enclosed in
meninges. It contains the majority of the nervous system, and consists of the
brain (in vertebrates which have brains), 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 brain is also protected by the skull, and the spinal cord is, in vertebrates, also protected by the vertebrae.
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.
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.
Central
nervous
system
| Brain |
Prosencephalon |
Telencephalon |
Rhinencephalon,
Amygdala,
Hippocampus,
Neocortex,
Lateral ventricles
|
| Diencephalon |
Epithalamus,
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
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
In addition to the structures seen to the right in table above, a vast number of structures are present in the adult brain.
Further Information
Get more info on 'Central Nervous System'.
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