| Term 
 
        | What two communication and control systems does the body have? |  | Definition 
 
        | Nervous system Endocrine system
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        | Term 
 
        | How does the nervous system communicate? |  | Definition 
 
        | via chemical messengers called neurotransmitters - produced only by neurons- neurotransmitters only travel short distances between nerve cells called synapses |  | 
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        | Term 
 
        | How does the endocrine system communicate? |  | Definition 
 
        | hormones - secreted in bloodstream - travel  long distances to reach their target cells - can be secreted long periods of time |  | 
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        | Term 
 
        | What is the function of a neuron? |  | Definition 
 
        | Basic functional unit of the system - respond to stimuli and conduct impulses from one part of the cell to another |  | 
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        | Term 
 
        | What is the function of neuroglia? |  | Definition 
 
        | They structurally and functionally support and protect the neurons. |  | 
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        | Term 
 
        | How long can a neuron survive without oxygen? |  | Definition 
 
        | Not more than a few minutes! |  | 
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        | Term 
 
        | What are the parts of a neuron? |  | Definition 
 
        | body - soma or perikaryon dendrites
 axon
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        | Term 
 | Definition 
 
        | They receive stimuli or impulses from other neurons and transmit it to the cell body. 
 considered to be afferent processes because they conduct impulses toward the body of the cell
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        | Term 
 
        | What is the function of the axon? |  | Definition 
 
        | They conduct impulses away from the cell body toward another neuron or effector cell. 
 considered to be efferent processes because they conduct impulses away from the cell body
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        | Term 
 | Definition 
 
        | Nervous tissue that is made up largely of neuron cell bodies - appears darker |  | 
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        | Term 
 | Definition 
 
        | Nervous tissue that contains many myelinated axons |  | 
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        | Term 
 | Definition 
 
        | Sheath of fatty substance that covers axons - appears white |  | 
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        | Term 
 
        | What are the Nodes of Ranvier? |  | Definition 
 
        | small gaps in the myelin sheath |  | 
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        | Term 
 
        | What is the relationship between the myelin sheath and the Nodes of Ranvier? |  | Definition 
 
        | they work together to enhance the speed of conduction of nerve impulses along the axon |  | 
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        | Term 
 | Definition 
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