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28 Cards in this Set
- Front
- Back
What are the functions (jobs) of the nervous system?
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Three:
1-Receiving information both inside and outside the body;2-responding to information; 3-Maintaining homeostatis |
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What are examples of how the nervous system receives information?
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Sight--you can see what is happening; hearing-- you can hear what is around you; feeling-- wind, cold, hot.
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How does the nervous system respond to information?
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An organism will respond to a stimulus
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What is a stimulus?
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a change or signal in the environment that makes an organism react or respond.
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What is a response?
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What your body does in reaction to a stimulus.
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What are the two types of responses to stimuli?
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Voluntary and involuntary
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What is homeostasis?
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the ability of your body to maintain equilibrium
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Give an example of how the nervous system maintains homeostasis.
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Telling you you are hungry when your body needs food; sweating when you get too hot; shivering when you get too cold
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What are neurons?
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cells that carry information through your nervous system.
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What is a nerve impulse?
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The message that a neuron carries
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What is the structure of a neuron?
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A large cell body that contains a nucleus and has threadlike extensions called nerve fibers.
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What are the two types of nerve fibers in a neuron?
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Dendrites-- carries impulses toward the cell body.
Axons-- carries impulses away from the cell body. |
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A bundle of nerve fibers is called a __________.
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Nerve
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How does the structure of a neuron enable it to carry nerve impulses?
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Nerve impulses begin in a dendrite, move toward the cell body and then move down the axon
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A neuron can have many __________ but only one ___________.
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A neuron can have many _dendrites but only one axon.
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How are nerve fibers arranged in the body?
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In parallel bundles covered with connective tissue. This bundle is called a nerve.
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How many types of neurons are found in the body?
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3- sensory neurons, interneurons and motor neurons.
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How do the 3 types of neurons work together? (Step 1)
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First a receptor in a sensory neuron picks up stimuli from the environment and converts the stimuli into a nerve impulse.
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How do the 3 types of neurons work together? (Step 2)
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Second, an interneuron carries the nerve impulse from one neuron to another. Some pass the impulse from a sensory neuron to a motor neuron.
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How do the 3 types of neurons work together? (Step 3)
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Third, a interneuron passes the impulse to a motor neuron which sends an impulse to a muscle. The muscle contracts in response.
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What is a synapse?
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The tiny space between each axon tip and the next structure-- either a dendrite of another neuron or a muscle or a cell in another organ.
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How does a nerve impulse travel?
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the impulse begins in the dendrites of a neuron, travels toward the cell body then down the axon until it reaches the axon tip. Then the axon tip releases chemicals that lets the impulse cross the synapse.
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What happens when a nerve impulse reaches the end of an axon?
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Chemicals are released into the synapes which enables the nerve impulse to cross the synapse
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What are the two divisions of the nervous system?
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The central nervous system and the peripheral nervous system
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What is the central nervous system?
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The brain and the spinal cord
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What is the peripheral nervous system?
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All the nerves located outside the central nervous system
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What part of the nervous system controls the most functions in the body?
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The brain
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What is the spinal cord?
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The column of nerve tissue that links the brain to most of the nerves in the peripheral nervous system
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