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Nervous System
The central nervous system is that part of the nervous system that consists of the brain and spinal cord. The central nervous system (CNS) is one of the two major divisions of the nervous system. The other is the peripheral nervous system (PNS) which is outside the brain and spinal cord. The peripheral nervous system (PNS) connects the central nervous system (CNS) to sensory organs (such as the eye and ear), other organs of the body, muscles, blood vessels and glands. The peripheral nerves include the 12 cranial nerves, the spinal nerves and roots, and what are called the autonomic nerves that are concerned specifically with the regulation of the heart muscle, the muscles in blood vessel walls, and glands.
Central Nervous System vs. Peripheral Nervous System
Citations: Central nervous system (CNS) definition - Medical Dictionary definitions of popular medical terms easily defined on MedTerms." Web. 18 Dec. 2009. . "WikiAnswers - What are the sense organs." WikiAnswers - The Q&A wiki. Web. 18 Dec. 2009. . "WikiAnswers - What is the difference between the sensory nerves and motor nerves." WikiAnswers - The Q&A wiki. Web. 18 Dec. 2009. . The Central Nervous System." RCN | Digital Cable TV, High-Speed Internet Service & Phone in Boston, Chicago, New York City, Philadelphia, Washington, D.C. and the Lehigh Valley. Web. 18 Dec. 2009. .
Sense Organs There are five sense organs and they each do something amazing for your body. The sense organs are your eyes, ears, tongue, nose and skin. The Sense of Sight Your eye is your sense of sight. First, light enters the eye throught the cornea. The cornea sends the light to the pupil, the dark center of hte eye. The Sense of Hearing you may not notice that the air vibrates when the sound id made. your ears, however, do notice. eardrum vibrations cause three small bones in the middle ear to vibrate. these bones- the hammer, anvil, and srirrup- pass the vibrations to a snail-part organ in the inner ear. The Sense of Smell and Taste Both your tongue and yoiur nose contain receptor cells, or cells that receive information. The receptor cells in your nose send messages throught the nerves. Your tongue can only recognize four different kinds of tastes. The four tastes are sweet,salty, sour, and bitter. The Sense of Touch Your skin, your sense organ for touch , is yior body's largest organ. Sense receptors all over your skin receive receive different sensations.
Sensory Nerves vs. Motor Nerves Sensory nerves are nerves that receive sensory stimuli, such as how something feels and if it is painful Motor nerves allow the brain to stimulate muscle contraction. A motor nerve is an efferent nerve that exclusively contains the axons of somatic and branchial motoneurons, which innervate skeletal muscles (that ensure locomotion) and branchial muscles (that motorize the face and neck).
Brain, Nerves, and Spinal Cord The brain- >>>receives sensory input from the spinal cord as well as from its own nerves >>>devotes most of its volume (and computational power) to processing its various sensory inputs and initiating appropriate — and coordinated — motor outputs. The Nerves- >>>The peripheral nervous system consists of more than 100 billion nerve cells that run throughout the body like strings, making connections with the brain, other parts of the body, and often with each other The Spinal Cord- >>>It connects a large part of the peripheral nervous system to the brain. Information (nerve impulses) reaching the spinal cord through sensory neurons are transmitted up into the brain. Signals arising in the motor areas of the brain travel back down the cord and leave in the motor neurons. >>>The spinal cord also acts as a minor coordinating center responsible for some simple reflexes like the withdrawal reflex.
