The nervous system
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Transcript of The nervous system
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The nervous system
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Nervous and endocrine systemsThe nervous and endocrine glands sys-
tems interact to control and coordi-nate the body’s
-responses to change in its environ-ment
-growth & development-reproduction
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A. Nervous system: Nervous con-trol depends mainly on the func-tioning of neurons (nerve cells).
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1. Stimulus: a change in the external or internal environment which initi-ates and impulse.
examples: vision, smell, taste, pres-sure, temperature, pain, equilibrium.
• A demonstration
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2. Impulse: an electro-chemical charge generated along a neuron.
• Electro-inside neuron• Chemical: between neurons
http://en.wikipedia.org/wiki/Action_potential
http://ffden-2.phys.uaf.edu/212_fall2003.web.dir/Casey_Adamson/Personal%20Web%20Page.htm
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3. Receptors: structures specialized to detect certain stimuli
4. Response: a reaction to a stimulus
http://meredithbond.com/blog/stimulus-and-response/
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5. Neuron: the basic cellular unit of the nervous system (specially designed for the transmission of impulses.) Our brain has millions of neurons.
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Neuron
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Neurona. Terminal branches: ends of axons
that secrete neurotransmitters.b. Synapse: gap between adjacent
neurons (terminal branches of one neuron and the dendrites of the next) or the gap between neuron and ef -fector.
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6. neurotransmitter• Neurotransmitter: chemical sub-
stance which starts the transmission of the nervous impulse (Acetyl-choline degraded by cholinesterase)
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Neurotransmitter con’t• Acetylcholine is the most common
neurotransmitter. • Dopamine is another neurotransmit-
ter that brings pleasure.
http://www.muscular-dystrophy.org/research/news/3262_study_compares_two_treatments_for_myasthenia_gravis
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Why do you think the nervous sys-tem is important?
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How do neurotransmitters work to trans-mit the nervous impulse in humans?
1. Nervous impulse travels down an axon to the tips of a terminal branch.
2. The terminal branch secretes neuro-transmitter into the synapse gap.
3. The neurotransmitter travels to the next neuron and causes depolarization of that neuron-thus a new nervous im-pulse is started in the next neuron.
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videoSynapse Structure and Function• http://www.youtube.com/watch?v=r
Wrnz-CiM7A
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• Neurons may release chemicals to stimulate each other. An example of a muscle being stimulated by a neu-ron appears after the reflex path pic-tured in number four in the diagram.
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• More complex animals have a central nervous system which includes a brain and a nerve cord (spinal cord).
• Brain: a large mass of neurons lo-cated in the cranial cavity—contains three major divisions.
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• Cerebrum: center for voluntary activity; in-terprets sensory impulses, initiates some motor activities, and responsible for mem-ory, thinking, and reasoning.
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• Cerebellum: coordinates motor activities and aids in maintaining balance.
• Medulla: controls involuntary activities such as breathing, heartbeat, blood pres-sure and peristalsis ( is part of the brain stem),
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Video The nervous systemhttp://www.youtube.com/watch?v=sjyI4CmBOA0
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Spinal cord: lies within, and is pro-tected by, the vertebrae of the spinal column.
http://www.quantumday.com/2012/06/walking-again-after-spinal-cord-injury.html
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-- is continuous with the brain coordi-nates activities between the brain and other body structures (bridge be-tween the brain and the peripheral nervous system)
-- it is also a center for reflex actions.
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Peripheral nervous system-- is located outside the central ner-
vous system and consists of the nerves extending throughout the body.
http://www.umm.edu/imagepages/8679.htm
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Peripheral nervous system1) somatic: voluntary control2) automatic: involuntary