Term
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Definition
| a type of glial cell that has numerous processes that contact capillaries & the lining of the cerebral ventricles |
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Term
| How do astrocytes serve important homeostatic functions? |
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Definition
| they control the concentrations of ions & the osmotic pressure of the ECF; help keep the neuronal environment optimal |
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Term
| What type of glial cell takes part in the repair process? |
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Definition
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Term
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Definition
| a type of glial cell that insulate axons by producing myelin sheaths in the CNS |
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Term
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Definition
| the macrophages of the nervous tissue |
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Term
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Definition
| a specialized form of glial cells that form myelin sheaths in the PNS |
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Term
| How are glial cells involved in the prenatal development of the nervous system? |
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Definition
| they provide surfaces & scaffoldings for migrating neurons & outgrowing axons |
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Term
| 3 categories of glial cells |
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Definition
1. astrocytes
2. oligodendrocytes
3. microglial cells |
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Term
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Definition
| a layer of cylindrical cells that line the surface of the cavities inside the CNS |
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Term
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Definition
| the special type of glial cell in the retina |
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Term
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Definition
| the special type of glial cell in the cerebellum |
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Term
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Definition
| the special type of glial cell in the pituitary gland |
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Term
| How do the numerous short or long processes of astrocytes help it to control the ECF environment? |
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Definition
| they have a large surface area that enables efficient exchange of ions & molecules with the ECF |
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Term
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Definition
| where astrocyte processes contact the surface of capillaries |
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Term
| What couple astrocytes to allow free passage of ions & other small particles among them? |
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Definition
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Term
| How do glial cells produce brief electric impulses despite not being able to send precise signals over long distances? |
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Definition
| they open membrane channels for Ca2+ |
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Term
| When activated, astrocytes increase local _____ |
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Definition
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Term
| Is K+ a relatively important ion? |
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Definition
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Term
| How do astrocytes contribute to extracellular pH? |
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Definition
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Term
| Why does extracellular neurotransmitter concentration need to be tightly controlled? |
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Definition
| proper synaptic functioning requires that their extracellular concentrations be very low, except during the brief moments of synaptic release |
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Term
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Definition
| proteins in the membranes of neurons & astrocytes that remove neurotransmitters from the ECF |
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Term
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Definition
| channels for the transport of water; present in the membranes of astrocytes |
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Term
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Definition
| the variety of aquaporin that is located in the astrocyte membrane & particularly concentrated in the end-feet region close to capillaries & in the glial processes bordering the CSF |
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Term
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Definition
| the type of aquaporin that is present in epithelial cells of the choroid plexus (place in brain that produces CSF) |
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Term
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Definition
| where water accumulates extracellularly in the brain |
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Term
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Definition
| when water accumulates intracellularly in the brain; caused by the failure of energy-dependent ion pumping which reduces the ability of the cells to maintain osmotic stability |
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Term
| Can damaged axons regenerate in the PNS? |
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Definition
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Term
| Can damaged axons regenerate in the CNS? |
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Definition
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Term
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Definition
| the layers of myelin formed when a glial cell wraps itself around the axon |
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Term
| Myelin has a high content of _____ |
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Definition
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Term
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Definition
| a type of membrane protein that binds the external sides of the membranes tightly together |
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Term
| myelin basic protein (MBP) |
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Definition
| a type of membrane protein that seals the cytoplasmic sides of the membranes in the myelin lamellae so that very little cytoplasm takes up space in the myelin sheath |
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Term
| When does myelination of axons start? |
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Definition
| prenatally (although many neural pathways are not 100% myelinated until age 2) |
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Term
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Definition
| interval interruptions of the myelin sheath along axons |
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Term
| What degenerates in a victim of MS? |
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Definition
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Term
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Definition
| the regions of axons that lose their myelin sheaths in MS victims |
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Term
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Definition
| a connective tissue in the PNS that is an external thick layer of mostly longitudinally running collagen fibers |
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Term
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Definition
| the smaller bundles of axons internal to the epineurium in the PNS & wrapped in the perineural sheath (perineurium) |
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Term
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Definition
| the collagen fibers & fibroblasts within the fascicles in the PNS |
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Term
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Definition
| prevents certain substances from reaching the interior of the fascicles with the axons; made from the perineurium in the PNS |
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Term
| What is the smallest type of glial cell? |
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Definition
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Term
| Microglial cells are of _____ origin |
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Definition
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Term
| After _____, the number of cells with phagocytic activity increases in the CNS |
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Definition
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Term
| Are microglial cells stagnant in a normal brain? |
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Definition
| no! they are constantly scanning their immediate environment for foreign material & sick or dead cellular elements |
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Term
| Do microglial cells serve to conserve homeostasis? |
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Definition
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Term
| Activation of microglial cells in the spinal cord seems to contribute to the persistence of _____ after nerve damage |
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Definition
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Term
| What is the main task of astrocytes after injury? |
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Definition
| strengthening their normal function of keeping the ECF composition constant |
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Term
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Definition
| diseases involving degeneration of peripheral nerves |
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Term
| Are most neuropathies inherited? |
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Definition
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