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26 Cards in this Set
- Front
- Back
nerve net |
A weblike system of neurons, characteristic of radically symmetrical animals, such as hydra. |
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nerve |
A ropelike bundle of neuron fibers (axons and dendrites) tightly wrapped in connective tissue. |
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central nervous system (CNS) |
In vertebrate animals, the brain and spinal cord. |
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ganglia |
A cluster (functional group) of nerve cell bodies in a centralized nervous system. |
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peripheral nervous system (PNS) |
The sensory and motor neurons that connect to the central nervous system. |
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sensory neuron |
A nerve cell that receives information from the internal and external environments and transmits the signals to the central nervous system. |
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interneuron |
An association neuron; a nerve cell within the central nervous system that forms synapses with sensory and motor neurons and integrates sensory input and motor output. |
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motor neuron |
A nerve cell that transmits signals from the brain or spinal cord to muscles or glands. |
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effector cell |
A muscle cell or gland cell that performs the body's responses to stimuli; responds to signals from the brain or other processing center of the nervous system. |
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reflex |
An automatic reaction to a stimulus, mediated by the spinal cord or lower brain. |
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cell body |
The part of a neuron that houses the nucleus and other organelles. |
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dendrite |
One of usually numerous, short, highly branched processes of a neuron that convey nerve impulses toward the cell body. |
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axon |
A typically long extension, or process, from a neuron that carries neuron impulses away from the cell body toward target cells. |
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axon hillock |
The conical region of a neuron's axon where it joins the cell body; typically the region where nerve signals are generated. |
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myelin sheath |
In a neuron, an insulating coat of cell membrane from Schwann cells that is interrupted by nodes of Ranvier, where saltatory conduction occurs. |
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synaptic terminal |
A bulb at the end of an axon in which neurotransmitter molecules are stored and released. |
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synapse |
The locus where one neuron communicates with another neuron in a neural pathway; a narrow gap between a synaptic terminal of an axon and a signal-receiving portion (dendrite or cell body) of another neuron or effector cell. Neurotransmitter molecules released by synaptic terminals diffuse across the synapse, relaying messages to the dendrite or effector. |
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presynaptic cell |
The transmitting cell at a synapse. |
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postsynaptic cell |
The target cell at a synapse. |
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neurotransmitters |
A chemical messenger released from the synaptic terminal of a neuron at a chemical synapse that diffuses across the synaptic cleft and binds to and stimulates the postsynaptic cell. |
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glia |
Supporting cells that are essential for the structural integrity of the nervous system and for the normal functioning of neurons. |
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astrocyte |
A glial cell that provides structural and metabolic support for neurons. |
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blood-brain barrier |
A specialized capillary arrangement in the brain that restricts the passage of most substances into the brain, thereby preventing dramatic fluctuations in the brain's environment. |
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radial glia |
In an embryo, supporting cells that form tracks along which newly formed neurons migrate from the neural tube; can also act as stem cells that give rise to neurons and other glia. |
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oligodendrocytes |
A type of glial cell that forms insulating myelin sheaths around the axons of neurons in the central nervous system. |
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Schwann cells |
A type of glial cell that forms insulating myelin sheaths around the axons of neurons in the peripheral nervous system. |