Term
| Types of neuroglia found in the CNS? |
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Definition
Astrocytes
Microglial cells
Ependymal cells
Oligodendrocytes |
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Term
| Types of neuroglia found in the PNS? |
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Definition
Schwann cells
Satellite cells |
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Term
| Type of neuroglia most abundant in the CNS? |
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Definition
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Term
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Definition
Connect neurons to nutrient supply and create a BBB.
Create a structural framework for CNS.
Guide neuron development.
Control interstitial environment. |
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Term
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Definition
Defensive (immune system) cells.
Transform into macrophage that phagocytize invading microorganisms. |
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Term
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Definition
Often ciliated.
Line central cavities of the brain and spinal cord.
Circulate cerebrospinal fluid surrounding the brain/spinal cord. |
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Term
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Definition
| Serve as insulation. Form myelin sheaths around nerve fibers. |
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Term
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Definition
| The measure of potential energy generated by separated electrical charges. Volts (V) or millivolts (mV). |
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Term
| Leakage (non-gated channels) |
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Definition
| Membrane channels that are always open. K+ and Na+ leaky channels found over entire cell. |
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Term
| Chemically Gated Channels (ligand-gated channels) |
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Definition
| Membrane channels that open when the appropriate chemical binds. Only on soma/dendrite. |
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Term
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Definition
| Membrane channels that open and close in response to changes in the membrane potential. |
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Term
| Mechanically Gated Channels |
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Definition
| Membrane channels that open in response to physical deformation of the receptor. Only on soma/dendrite. |
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Term
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Definition
| A decrease in membrane potential. The inside of the membrane becomes less negative (moves closer to zero) than the resting potential |
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Term
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Definition
| An increase in membrane potential. The inside of the membrane becomes more negative (moves farther from zero) than the resting potential. |
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Term
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Definition
| Restores membrane to resting electrical conditions. |
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Term
| Graded Potentials (dendrites and somas) |
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Definition
| Short-lived localized changes in membrane potential. Can be either depolarization or hyperpolarizations. |
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Term
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Definition
| Magnitude varies directly with stimulus strength. Stronger the stimulus, the more voltage changes and the farther the current flows. |
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Term
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Definition
| Brief, long-distance signal within a neuron. Depolarization is followed by repolarization and often a short period of hyperpolarization. |
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Term
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Definition
| Activated by local graded potentials from the dendrites and somas that spread toward the axon. |
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Term
| Excitatory Postsynaptic Potentials (EPSPs) |
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Definition
| Type of Graded Potential that is a local depolarization of the postsynaptic membrane. |
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Term
| Inhibitory Postsynaptic Potentials (IPSPs) |
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Definition
| A type of Graded Potential where inhibitory neurotransmitters hyperpolarize the postsynaptic membrane by making it more permeable to K+ or Cl-. |
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Term
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Definition
| Converts chemical signals to electrical signals and mediate graded potentials that vary in strength based on the amount of neurotransmitter released and how long it remains in the area. |
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Term
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Definition
| An AP either happens or it doesn't. An AP is generated when enough Na+ enters the cell and reaches threshold. The AP is generated and propagated whether or not the stimulus continues, but if there are not enough Na+ ions to reach threshold, and AP will not occur. |
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Term
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Definition
| Occurs when one presynaptic neuron transmit impulses in rapid fire order and bursts of neurotransmitter are released in quick succession. |
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Term
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Definition
| Occurs when the postsynaptic neuron is stimulated simultaneously by a large number of terminals from many presynaptic neurons. |
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Term
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Definition
| When a patch of neuron membrane is generating an AP and its voltage-gated sodium channels are open, the neuron cannot respond to another stimulus no matter how strong. |
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Term
| Relative Refractory Period |
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Definition
| Follows an absolute refractory period and occurs when an exceptionally strong stimulus reopen the Na+ channels that have already returned to their resting state and generate another AP. |
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Term
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Definition
| How an AP moves along an axon's entire length to serve as the neuron's signaling device. |
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Term
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Definition
| In myelinated axons, APs are generated only in the myelin sheath gaps and jump from gap to gap. Myelin keeps current in the axons. |
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Term
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Definition
| Neuron conducting impulses toward the synapse. |
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Term
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Definition
| Neuron transmitting the electrical signal away from the synapse. |
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Term
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Definition
| Junction that mediates information transfer from one neuron to the next or an effector cell. |
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