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15 Cards in this Set
- Front
- Back
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Nervous system organization
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Central portion and peripheral
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Central Nervous system
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brain and spinal cord
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Peripheral portion
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divided into somatic/ voluntary and autonomic/involuntary has sensory receptors in the skin to messages in and motor neurons for messaging out
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Autonomic portion
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divided into sympathetic branch of fight or flight and the parasympathetic branch for resting and digesting (homeostasis)
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Nervous system is ____ kg in weight and ____ % total; smallest but most complex
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2 kg and 3 %
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Neuroglia
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Able to divide, neurons cannot. Astrocytes and oligodendrocytes can, they are a part of neuroglia
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Astrocytes
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support neurons; steal beam like structure to nervous tissue
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Oligodendrocytes
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Allow directed impulse activity; wires analogy. They make lipid insulation in the CNS
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Myelin sheath
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multilayered protein/lipid coverind; ONLY in the CNS. Spaced myelin on an axon allow signals to jumper for fast electrical conduction
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Schwann cells
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make the myelin sheath for the PNS axons
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Satellite cells
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Support and regulate; maintain
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Nerves
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NOT neurons, they are 1000's of bundles of an axon that conduct the signals and must be clustered together with connective tissue and blood vessels. Part of a neuron.
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Brain
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has 100 billion neurons
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Spinal cord
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100 million neurons; all single cells
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ganglia
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small masses of nervous tissue
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