Information AboutNervous System |
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| nervous systemnervous system | |
| animal anatomy | |
| neurology | |
| neuroanatomy | |
| neurophysiology | |
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The nervous system of an Animal coordinates the activity of the Muscle s, monitors the Organ s, constructs and also stops input from the Sense s, and initiates Action s. Prominent parts of a nervous system include Neuron s and Nerve s, which are used in coordination. All parts of the nervous system are made of Nervous Tissue . The classification of the nervous system is mostly similar in humans as in other vertebrates. HUMANS The nervous system of Humans is often divided into the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS consists of the Brain and Spinal Cord . Central nervous system See Also: Central nervous system See Also: List of regions in the human brain 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 subcavity, 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. Peripheral nervous system See Also: Peripheral nervous system The PNS consists of all other nerves and neurons that do not lie within the CNS. The large majority of what are commonly called nerves (which are actually axonal processes of nerve cells) are considered to be PNS. The peripheral nervous system can be further classified either by direction of Neurons and by function. By direction There are three types of directions of the Neurone s:
The junction between two neurones is called a Synapse . There is a very narrow gap between the neurones - the Synaptic Cleft . By function By function, the peripheral nervous system is divided into the Somatic Nervous System and the Autonomic Nervous System . The Somatic Nervous System is responsible for coordinating the body's movements, and also for receiving external stimuli. It is the system that regulates activities that are under conscious control. The Autonomic Nervous System is then split into the Sympathetic Division , Parasympathetic Division , and Enteric Division . The sympathetic nervous system responds to impending danger or stress, and is responsible for the increase of one's heartbeat and blood pressure, among other physiological changes, along with the sense of excitement one feels due to the increase of adrenaline in the system. The parasympathetic nervous system, on the other hand, is evident when a person is resting and feels relaxed, and is responsible for such things as the constriction of the pupil, the slowing of the heart, the dilation of the blood vessels, and the stimulation of the digestive and Genitourinary systems. The role of the enteric nervous system is to manage every aspect of digestion, from the esophagus to the stomach, small intestine and colon. VERTEBRATES The nervous system of all vertebrate animals, is often divided into the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS consists of the brain and spinal cord. WORMS Planaria , a type of Flatworm , have dual Nerve Cord s running along the length of the body and merging at the tail and the mouth. These nerve cords are connected by Transverse nerves like the rungs of a ladder. These transverse nerves help Coordinate the two sides of the animal. Two large Ganglia at the head end function similar to a simple brain. Photoreceptor s on the animal's eyespots provide sensory information on light and dark. The nervous system of the Roundworm '' Caenorhabditis Elegans '' has been mapped out to the cellular level. Every neuron and its Cellular Lineage has been recorded and most, if not all, of the neural connections are known. In this species, the nervous system is Sexually Dimorphic ; the nervous systems of the two sexes, males and Hermaphrodites , have different numbers of neurons and groups of neurons that perform sex-specific functions. In ''C. elegans'', males have exactly 383 neurons, while hermaphrodites have exactly 302 neurons {Link without Title} ARTHROPODA on each side, though some ganglia are fused to form the brain and other large ganglia {Link without Title} . 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 Muscle s. Many arthropods have well-developed Sensory organs, including Compound Eye s for vision and Antennae for Olfaction and Pheromone sensation. The sensory information from these organs is processed by the brain. SEE ALSO
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