The nervous system of an animal coordinates the activity of the muscles, monitors the organs, constructs and processes input from the senses and initiates actions.
In animals with brains, the nervous system also generates and conducts thoughts and emotions. Thus it is the system that animates "animals" (sponges are an exception). Chemicals that target the activity of nerves generally are the most rapidly acting toxins, typically causing paralysis and/or death.
Anatomy of the nervous system
The nervous system consists basically of two types of cells:
· Neurons are the primary cells of the nervous system
· Glia are secondary cells involved in nourishment and structural support.
Rapid signalling within the nervous system occurs by two primary mechanisms:
· Within neuronal nerve fibers by way of action potentials
· Between neurons by way of neurotransmitter diffusion across synapses.
Vertebrate nervous systems
For heuristic and other purposes, the nervous systems of vertebrate animals are often divided into a central (CNS) and a peripheral nervous systems (PNS). The CNS consists of the brain and spinal cord. The PNS consists of sensory pathways and motor pathways, the latter being divided into the somatic (voluntary) nervous system and the autonomic nervous system.
The somatic nervous system is the voluntary part of the nervous where it coordinates the movement such as posture and walking. The autonomic nervous system is the involuntary part of the nervous system where all of the internal maintenance is taken care of.
The autonomic nervous system is then divided into the sympathetic division and parasympathetic division. The sympathetic nervous system is responsible for the excitment that a person feels due to the increase of heartbeat. The parasympathetic nervous system, on the other hand, is the opposite of the sympathetic nervous system. This system is in play when a person is resting and feels relaxed due to the slowing down of the heartbeat.
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The Nervous System Anatomical Chart Author: Anatomical Chart CompanyDescriptionFeaturing classic illustrations by Peter Bachin, this chart shows nerves in the body, brain, midbrain, medulla oblongata, and spinal cord. Spinal meninges, intercostal nerves, and sagittal section of female pelvis are also shown.  |
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The Nervous System Anatomical Chart Author: Anatomical Chart CompanyDescriptionFeaturing classic illustrations by Peter Bachin, this chart shows nerves in the body, brain, midbrain, medulla oblongata, and spinal cord. Spinal meninges, intercostal nerves, and sagittal section of female pelvis are also shown. |
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Author: MobileReferenceDescriptionBoost your grades with this illustrated Study Guide. Navigate from Table of Contents or search for words or phrases. FREE Neurocellular Anatomy chapter in the trial version. Audience: Intended for everyone interested in human nervous system, particularly undergraduate and graduate life science students, medical students, nursing students, physician assistants students, and physical therapy students... |
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The Nervous System (New True Books: Health) Author: Christine Taylor-ButlerDescriptionDid you know that your nerve impulses are 1,000 times SLOWER than your computer? Or that it's normal to fart - as often as 20 times a day? Get the buzz on health and the human body with this fun and fascinating series. |
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An Introduction to Nervous Systems Author: Ralph J. GreenspanDescriptionAn Introduction to Nervous Systems presents the principles of neurobiology from an evolutionary perspective from single celled organisms to complex invertebrates such as flies and is ideal for use as a supplemental textbook... |
Tags: Central nervous system, Human Interest, Smithsonian Tropical Research Institute, Nervous system, the nervous system, typically causing paralysis, Health Medical Pharma