Nervous System – Flashcards
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Central Nervous System (CNS)
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directs all activity of entire nervous system; composed of brain and spinal cord
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Peripheral Nervous System (PNS)
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composed of cranial nerves and spinal nerves that transmit to and from the brain and spinal cord
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Afferent nerves
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sensory nerves; transmit impulses from the sensory receptors in the skin, muscles, and joints to the CNS
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Efferent nerves
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motor nerves; carry impulses from the CNS out to the muscles and glands
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Somatic Nervous System
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voluntary; stimulates skeletal muscles, causing them to develop tension
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Autonomic Nervous System
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involuntary; controls cardiac muscle of heart and smooth muscle of internal organs
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Sympathetic nervous system
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"fight-or-flight"
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Parasympathetic nervous system
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"rest-or-digest"
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Neuroglia
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glial cells; specialized cells that perform support functions
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Astrocytes
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link nutrient-supplying capillaries to neurons and control the chemical environment to protect neurons from harmful substances in the blood
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Microglia
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absorb and dispose of dead cells and bacteria
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Ependymal cells
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form a protective covering around spinal cord and central cavities within the brain
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Oligodendrocytes
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wrap around nerve fibers and produce a fatty insulating material called myelin
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Schwann cells
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from myelin sheaths around nerve fibers in the PNS
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Satellite cells
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serve as cushioning support cells
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Cell body
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where a nucleus and mitochondria are found in a neuron
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Dendrites
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collect stimuli and transport it to cell body
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Axon
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transmits impulses away from the cell body
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Myelin sheath
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insulates the axon fibers and increases the rate of neural impulse transmission
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Neurilemma
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external covering of Schwann cell
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Nodes of Ranvier
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uninsulated gaps where axon is exposed between the Schwann cells
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Neurotransmitters
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chemical messengers used in the brain
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Reflexes
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simple, rapid, involuntary, programmed responses to stimuli
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Somatic reflexes
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Involve stimulation of skeletal muscles
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Autonomic reflexes
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Send involuntary stimuli to the cardiac and smooth muscle
