Term
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Definition
| specialized (albeit relatively rare) intercellular continuities between some neurons; similar to those found in epithelia such as the lung & intestine |
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Term
| 2 broad categories of cells of the nervous system |
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Definition
1. nerve cells/neurons
2. glial cells (AKA neuroglia/glia) |
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Term
| nerve cells are specialized for _____ |
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Definition
| electrical signaling over long distances |
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Term
| what is the purpose of glial cells? |
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Definition
| glial cells support rather than generate electrical signals; essential contributors to repair of the damaged nervous system (acting as stem cells in some brain regions, promoting regrowth of damaged neurons, & preventing dangerous regeneration) |
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Term
| 2 important aspects of the branching typical of nerve cells are the presences of _____ |
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Definition
1. axons
2. dendrites (arise from the cell body in the form of dendritic branches) |
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Term
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Definition
| the primary targets for synaptic input from the axon terminals of other neurons |
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Term
| dendrites are distinguished by their high concentrations of _____ & specific _____ |
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Definition
| ribosomes; cytoskeletal proteins |
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Term
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Definition
| the number of inputs to a single neuron |
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Term
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Definition
| the number of targets innervated by any one neuron |
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Term
| pre- and postsynaptic components communicate not through physical continuity, but through _____ |
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Definition
| the secretion of molecules from the presynaptic terminal that bind to receptors in the postsynaptic cell |
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Term
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Definition
| the interval of extracellular space between pre- and postsynaptic elements that communication molecules must traverse |
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Term
| relatively short axons are a feature of _____ |
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Definition
| local circuit neurons/interneurons (usually throughout the brain) |
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Term
| axons of _____ extend to distant targets |
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Definition
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Term
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Definition
| carries signals over long distances; an all-or-nothing change in the electrical potential (voltage) across the nerve cell membrane that conveys information from one point to another in the nervous system |
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Term
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Definition
| the point of initiation at the cell body of an action potential |
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Term
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Definition
| the chemical & electrical processes by which the information encoded by action potentials is passed on at synaptic contacts to a target cell |
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Term
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Definition
| presynaptic terminals & their postsynaptic specializations |
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Term
| the most abundant type of synapse in the nervous system is _____ |
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Definition
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Term
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Definition
| facilitated by gap junctions |
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Term
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Definition
| the secretory organelles in the presynaptic terminal of chemical synapses |
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Term
| neurotransmitter molecules/neurotransmitters |
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Definition
| what fills synaptic vesicles |
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Term
| three main types of nerve systems |
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Definition
1. sensory systems
2. motor systems
3. associational systems |
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Term
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Definition
| acquire & process information from the environment |
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Term
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Definition
| respond to information by generating movements & other behavior |
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Term
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Definition
| mediate most complex & least well characterized brain functions |
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Term
| central nervous system (AKA CNS) |
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Definition
| the brain & the spinal cord |
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Term
| peripheral nervous system/PNS |
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Definition
| sensory neurons that link sensory receptors on the body surface or deeper within it with relevant processing circuits in the central nervous system |
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Term
| 2 motor portions of the peripheral nervous system |
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Definition
1. somatic motor division
2. visceral/autonomic motor division |
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Term
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Definition
| the motor axons that connect the brain & spinal cord to skeletal muscles |
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Term
| visceral/autonomic motor division |
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Definition
| the cells & axons that innervate smooth muscles, cardiac muscle. & glands |
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Term
| the nerve cell bodies that reside in the peripheral nervous system are located in _____ |
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Definition
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Term
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Definition
| bundles of peripheral axons |
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Term
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Definition
| local accumulations of neurons that have roughly similar connections & functions |
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Term
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Definition
| sheet-like arrays of nerve cells |
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Term
| axons in the central nervous system are gathered into _____ |
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Definition
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Term
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Definition
| tracts that cross the midline of the brain |
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Term
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Definition
| any accumulation of cell bodies & neuropil in the brain & spinal cord |
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Term
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Definition
| axon tracts & commissures (relatively light in appearance because of the lipid content of myelin) |
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Term
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Definition
| the peripheral motor neurons that control most involuntary behavior |
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Term
| sympathetic division of the autonomic motor system |
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Definition
| ganglia lie along or in front of the vertebral column & send their axons to a variety of peripheral targets |
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Term
| parasympathetic division of the autonomic motor system |
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Definition
| ganglia are found within or adjacent to the organs they innervate |
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Term
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Definition
| made up of small ganglia as well as individual neurons scattered throughout the wall of the gut; part of the autonomic motor division |
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Term
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Definition
| a type of glial cell; restricted to the central nervous system, have elaborate local processes that give these cells a starlike ("astral") appearance; maintain an appropriate chemical environment for neuronal signaling |
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Term
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Definition
| type of glial cell; restricted to the central nervous system; lay down myelin around some axons |
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Term
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Definition
| a laminated, lipid-rich wrapping; effects the speed of the transmission of electrical signals |
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Term
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Definition
| cells that provide myelin in the peripheral nervous system |
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Term
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Definition
| type of glial cell; derived primarily from hematopoietic precursor cells; remove cellular debris from sites of injury or normal cell turnover |
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Term
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Definition
| retain the capacity to proliferate & generate additional precursors or differentiated glia & neurons |
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