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| a nerve cell that receives information from the internal or external environment and transmits signals to the central nervous system |
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| a nerve cell that transmits signals from the brain or spinal cord to muscles or glands |
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| an association neuron; a nerve cell within the central nervous system that forms synapses with sensory and/or motor neurons and integrates sensory input and motor output |
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| the part of a neuron that houses the nucleus and most other organelles |
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| one of usually numerous, short, highly branced extensions of a neuron that receive signals from other neurons |
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| a typically long extension, or process, of a neuron that carries nerve impulses away from the cell body toward target cells |
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| the junction where a neuron communicates with another cell across a narrow gap via a neurotransmitter or an electrical coupling |
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| passes information across the synapse in the form of chemical messengers called neurotransmitters |
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| the cone-shaped base of the axon |
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| a molecule that is released from the synaptic terminal of a neuron at a chemical synapse, diffuses across the synaptic cleft, and binds to postsynaptic cell, triggering a response |
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| cells of the nervous system that support, regulate, and augment the functions of neurons |
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| a type of glial cell that forms insulating myelin sheaths around the axons of neurons in the periperal nervous system |
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wrapped around the axon of a neuron, an insulating coat of cell membranes from Schwann cells or oligodendrocytes
it is interrupted by nodes of Ranvier where action potentials are generated |
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| the membrane potential charasteristic of a nonconducting excitable cell, with the inside of the cell more negative than the outside |
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| an electrical signal that propagates (travels) along the membrane of a neuron or other excitable cell as a nongraded (all-or-none) depolarization |
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a change in cell's membrane potential such that the inside of the membrane becomes more negative relative to the outside
hyperpolarization reduces the change that a neuron will transmit a nerve impulse |
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Definition
| a change in cell's membrane potential such that the inside of the membrane is made less negative relative to the outside |
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| the potential that an excitable cell membrane must reach for an action potential to be initiated |
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| the short time immediately after an action potential in which the neuron cannot respond to another stimulus, owing to the inactivation of volate-gated sodium channels |
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gap in the myelin sheath of certain axons wehre an action potential may be generated
in saltatory conduction, an action potential is regenerated at each node, appearing to "jump" along the axon from node to node |
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Definition
| rapid transmission of a nerve impulse along an axon, resulting from the action potential jumping from one node of Ranvier to another, skipping the myelin-sheathed regions of membrane |
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| a transmembrane protein containing a pore that opens or closes as it changes shape in response to a signaling molecule (ligand), allowing or blocking the flow of specific ions |
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| Excitatory postsynaptic potential (EPSP) |
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Definition
an electrical change (depolarization) in the membrane of a postsynaptic cell caused by the binding of an excitatory neurotransmitter from a presynaptic cell to a postsynaptic receptor
makes it more likely for a postsynaptic cell to generate an action potential |
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| Inhibitory postsynaptic potential (IPSP) |
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Definition
an electrical change (usually hyperpolarization) in the membrane of a postsynaptic neuron caused by the binding of an inhibitory neurotransmitter from a presynaptic cell to postsynaptic receptor
makes it more difficult for a postsynaptic neuron to generate an action potential |
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| Peripheral nervous system |
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Definition
| the sensory and motor neurons that connect to the central nervous system |
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the portion of the nervous system where signal integration occurs
in vertebrates, the brain and spinal cord |
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