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40 Cards in this Set
- Front
- Back
axon hillock |
juncture of soma (cell body) and axon |
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dendrite |
branching extension of a neuron's cell membrane; greatly increases the cell's surface area; collects information from other cells |
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connectome |
comprehensive map of all structural connectivity (the physical wiring) in an organism's nervous system |
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ependymal cell |
glial cell that makes and secretes CSF; found on the walls of the brain's ventricles |
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astrocyte |
star-shaped glial cell that provides structural support to CNS neurons and transports substances between neurons and blood vessels |
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blood-brain barrier |
tight junctions between the cells that compose blood vessels in the brain, providing a barrier to the entry of an array of substances, including toxins, into the brain |
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microglia |
glial cells that originate in the blood, aid in cell repair, and scavenge debris in the nervous system |
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myelin |
glial coating that surrounds axons in the central and peripheral nervous systems; prevents adjacent neurons from short-circuiting |
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oligodendroglia |
glial cells in the CNS that myelinate axons |
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Schwann cell |
glial cell in the PNS that myelinates sensory and motor axons |
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resting potential |
electrical charge across the insulating cell membrane in the absence of stimulation; a store of potential energy produced by a greater negative charge on the intracellular side relative to the extracellular side |
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graded potential |
small voltage fluctuation across the cell membrane |
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action potential |
large, brief reversal in the polarity of an axon membrane |
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threshold potential |
voltage on a neural membrane at which an action potential is triggered by the opening of sodium and potassium voltage-sensitive channels; about -50 mV relative to extracellular surround (also called threshold limit) |
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absolutely refractory |
the state of an axon in the repolarizing period, during which a new action potential cannot be elicited (with some exceptions), because gate 2 of sodium channels, which are not voltage sensitive, are closed |
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relatively refractory |
the state of an axon in the later phase of an action potential during which increased electrical current is required to produce another action potential; a phase during which potassium channels are still open |
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node of Ranvier |
the part of an axon that is not covered by myelin |
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saltatory conduction |
fast propagation of an action potential at successive nodes of Ranvier (saltatory means leaping) |
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EPSP (excitatory postsynaptic potential) |
brief depolarization of a neuron membrane in response to stimulation, making the neuron more likely to produce an action potential |
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IPSP (inhibitory postsynaptic potential) |
brief hyperpolarization of a neuron membrane in response to stimulation, making the neuron less likely to produce an action potential |
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synaptic vesicle |
membranous compartment that encloses a quantum of neurotransmitter |
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synaptic cleft |
gap separating the neuronal presynaptic membrane from the post synaptic membrane |
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histamine (H) |
neurotransmitter that controls arousal and waking; can cause the constriction of smooth muscles; when activated in allergic reactions, constricts airway and contributes to asthma |
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glutamate (Glu) |
amino acid neurotransmitter; typically excites neurons |
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GABA (gamma-aminobutyric acid) |
amino acid neurotransmitter; typically inhibits neurons |
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endocannabinoid |
class of lipid neurotransmitters, including anandamide and 2-AG, synthesized at the postsynaptic membrane to act on receptors at the presynaptic membrane; affects appetite, pain, sleep, mood, memory, anxiety, and the stress response |
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ionotropic receptor |
embedded membrane protein; acts as a binding site for a neurotransmitter and a pore that regulates ion flow to directly and rapidly change membrane voltage |
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metabotropic receptor |
embedded membrane protein with a binding site for a neurotransmitter linked to a G protein; can affect other receptors or act with second messengers to affect other cellular processes, including opening a pore |
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G protein |
guanyl nucleotide-biding protein coupled to a metabotropic receptor; when activated, binds to other proteins |
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autoreceptor |
self-receptor in a neuronal membrane; that is, it responds to the same transmitter released by the neuron |
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agonist |
substance that enhances synapse function |
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antagonist |
substance that blocks synapse function |
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monoamine oxidase (MAO) inhibitor |
antidepressant drug that blocks the enzyme monoamine oxidase from degrading such neurotransmitters as DA, NE, and 5-HT |
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tricyclic antidepressant |
first-generation antidepressant; its chemical structure, characterized by three rings, blocks 5-HT reuptake transporter proteins |
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selective serotonin reuptake inhibitor (SSRI) |
tricyclic antidepressant drug that blocks 5-HT reuptake into the presynaptic terminal |
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mood stabilizer |
drug for treating bipolar disorder; mutes the intensity of one pole of the disorder, thus making the other pole less likely to recur |
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disinhibition theory |
explanation holding that alcohol has a selective depressant effect on the brain's frontal cortex, which controls judgment, while sparing subcortical structures responsible for more instinctual behaviors, such as desire |
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wanting-and-liking theory |
explanation holding that when a drug is associated with certain cues, the cues themselves elicit desire for the drug (also called incentive sensitization theory) |
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glucocorticoid |
one of a group of steroid hormones, such as cortisol, secreted in times of stress; important in protein and carbohydrate metabolism |
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organizational hypothesis |
proposal that hormonal action during development alters tissue differentiation; for example, testosterone masculinizes the brain |