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48 Cards in this Set
- Front
- Back
Organs of the Nervous System
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The brain, the spinal cord, the numerous nerves of the body, the specialized sense organs such as the eyes and ears, and the microscopic sense organs.
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Two principal divisions of the Nervous System
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The central nervous system and the peripheral nervous system.
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Central Nervous System
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Made up of the brain and spinal cord.
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Peripheral Nervous System
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The nerves connecting the brain and spinal cord to other parts of the body.
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Autonomic Nerous System
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A subdivision of the peripheral nervous system that consists of structures that regulate the body's automatic or involuntary functions (heart rate, contractions of stomach)
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Two types of cells found in the nervous system
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Neurons and glia.
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Neurons
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Nerve Cells, conduct impulses.
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Glia
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Specialized connective tissue cells, they support neurons.
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3 parts of neuron
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Cell body, dendrites, axon.
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Cell Body
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Main part of a neuron.
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Dendrites
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Branchlike projections on a neuron, transmit impulses to the neuron cell bodies.
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Axon
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One elongated projection on a neuron, transmit impulses away from the neuron cell bodies.
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3 types of nerons
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Sensory neurons, motor neurons, interneurons.
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Sensory Neurons (Afferent)
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Transmit impulses to the spinal cord and brain from all parts of the body.
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Motor Neurons (Efferent)
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Transmit impulses away from the brain and spinal cord to muscle and glandular epithelial tissue.
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Interneurons (Central or Connecting)
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Conduct impulses from sensory neurons to motor neurons.
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Myelin
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A white, fatty substance formed by Schwann Cells that wrap around some axons outside the central nervous system.
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Schwaan Cells
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Large nucleated cells that form myelin.
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Nodes of Ranvier
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Indentations between adjacent Schwaan cells.
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Neurilemma
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The outer cell membrane of a Schwaan Cells.
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Functions of Glia
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Hold the functioning neurons together and protect them.
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Glioma
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Brain tumor develops from glia.
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Astrocytes
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Glia that are large and look like stars because of threadlike extensions which attach to blood vessels.
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Blood-brain barrier
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Separates the blood tissue and nervous tissue to protect the brain, made up of astrocytes.
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Microglia
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Smaller than astrocytes, usually remain stationary, but in inflamed or degenerating brain tissue, they enlarge moveabout, and act as microbe-eating scavengers.
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Oliogodendrocytes
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Help to hold nerve fibers together and also produce the fatty myelin sheath that envelops nerve fibers.
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Nerve
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A group of peripheral nerve fibers bundled together like strands of a cable, also called the white matter of the PNS.
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Tracts
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Bundles of axons in the CNS,
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Gray Matter
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Tissue comprising cell bodies and unmyleinated axons and dendrites.
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Endoneurium
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The thin wrapping of fibrous connective tissue that surrounds each axon in a nerve.
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Fascicles
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Groups of wrapped axons.
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Perineurium
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Surrounds each fascicle.
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Epineurium
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A tough fibrous sheath that covers the whole nerve.
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Reflex Arc
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Allows an impulse to travel in only one direction
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Receptors
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Peripheral beginning of a sensory neuron's dendrite.
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Ganglion
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a region of gray
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Reflex
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Involuntary action
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Nerve Impulse
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Self propagating wave of electircal disturbance that travels along the surface of a neuron's plasma membrane.
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Saltatory Conduction
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When a nerve impulse encounters myelin and "jumps" from one node of Ranvier to the next.
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Presynaptic neuron
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A neuron situated proximal to a synapse.
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Postsynaptic Neuron
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A neuron situated distal to a synapse.
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Synaptic Knob
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A tiny bulge at the end of a terminal brance of a presynaptic neuron's axon that contains vesicles with neurotransmitters.
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Neurotransmitter
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Chemicals by which neurons communicate.
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Synaptic Cleft
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A space between a synaptic knob and the plasma membrane of a postynaptic neuron.
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Acetylcholine
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Chemical neurotransmitter.
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Well-known neurotransmitters
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Norepinephrine, dopamine, serotonin.
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Catecholamines
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Norepinephrine and epindephrine. Play a role in sleep, motor function, mood, and pleasure recognition.
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Morphinelike Neurotransmitters
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Endorphines, enkephalines. Natural pain killers.
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