Term
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Definition
| a juction between 2 neurons across which a nerve signal is conducted |
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Term
| pre-synaptic neuron does what? |
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Definition
| conducts information to synapse |
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Term
| post-synaptic neuron does what? |
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Definition
| conducts information away from synapse |
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Term
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Definition
| separation between synaptic knob of presynaptic neuron and membrane of post synaptic neruon |
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Term
| how many synapses may a single neuron in the cerebellum have? |
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Definition
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Term
| synapse may be 3 things axo-? |
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Definition
| axodendritic, axosomatic, axoaxonic |
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Term
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Definition
| when a nerve signal is transmitted by flow of ions from one cell to another through gap juctions |
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Term
| function of electrical synapse |
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Definition
| allow fast communication, synchronization among multiple neurons or muscle fibers, two-way transmission of signals |
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Term
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Definition
| nerves signal is transmitted by small organic transmitters |
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Term
| 4 things neurontransmitters bo in chemical synapes |
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Definition
-neurontransmitters is synthesized by pre-synaptic neuron and stored in vesicles
-are released frim pre-synaptic neuron in response to stimulus
-bind to specific receptors on post-synaptics neurons
-alter physiology of post-syanptic neuron |
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Term
| how many substances can be classified as neurotrasmitters |
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Definition
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Term
| neurotransmitter acetycholine (Ach) |
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Definition
| most familiar and can be excitatory or inhibitory |
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Term
| amino acids as neurotransmitters |
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Definition
| can be excitatory of inhibitory |
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Term
| biogenic amines as neurotrasmitters |
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Definition
| are modifies amino acids that may be excitatory or inhibitory |
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Term
| neuropeptides as neurotransmitters |
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Definition
| amino acid chains that may be excitatory or inhibitory |
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Term
| neuropeptides as neuromodulators |
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Definition
| some are and function like hormones |
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Term
| neuropeptides may be responsible for what? |
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Definition
| craving fat and/or sugar and may cause some eating disorders |
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Term
| achetylcholine is the neurotransmitter where? |
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Definition
| at an excitatory cholenergic synapse |
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Term
| what does the arrival of a nerve signal at a pre-synaptic knob do? |
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Definition
| opens voltage-gated calcium channels |
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Term
| what is the role of Ca+2 ot an exitatory cholinergic synapse? |
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Definition
| Ca+2 enter pre-synaptic knob and trigger exocytosis of synaptic vesicles that release Ach into synaptic cleft |
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Term
| what happens to the empty vesicles after the Ach has been released into synaptic cleft? |
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Definition
| empty vesicles are refilled with Ach |
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Term
| where does Ach diffuse after being released into synaptic cleft? |
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Definition
| diffuses across synaptic cleft and binds with recpetors on postsynaptic membrane |
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Term
| what happens when ligand-regualted gates open? |
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Definition
| Na+1 enter post-synaptic neuron, K+1 leaves post-synaptic membrane |
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Term
| what may happen as a reseult of the postsynaptic potential? |
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Definition
| may trigger action potential if it is strong enough to depolarize post-synaptic membrane to threshold |
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Term
| what neurontransmitter is at an inhibitory synapse? |
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Definition
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Term
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Definition
| like Ach, except it opens chloride channels and hyper polarizes post-synaptic membrane making it harder to generate action potential |
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Term
| what neurotrasmitter is at an excitatory adrenergic synapse? |
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Definition
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Term
| how does norepinephrine work? |
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Definition
| operates by second-messenger system that activates transmembrane G protein binding it to adenylate cyclasm |
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Term
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Definition
| catalyzes conversion of ATP to cAMP |
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Term
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Definition
-binds to ligand-regualted ion gat on inside of membrane and opens it to depolarize membrane
-activates cytoplasmic enzymes that catalyze changes in metabolic reactions
-also induces transcription |
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Term
| what must happen to stop the transmission of nerve signals? |
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Definition
| neurotransmitters must be removed from synaptic cleft |
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Term
| how can neurotrasmitters be removed from a synaptic cleft? [3] |
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Definition
-they can diffuse out of synaptic cleft into ECF where they get absorbed by astrocytes to be returned to the pre-synaptic neuron
-they can be actively transported back into neuron that released them
-Ach can be degenerated by acetylcholinesterase |
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Term
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Definition
| grade potentials whose size varies according to strength of stimulus and amount of neurotransmitter that was released |
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Term
| when does excitartoy postsynaptic potential (EPSP) occur? |
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Definition
| if neurotrasmitter causes depolarization of post-synaptic membrane because Na+1 flow into cell |
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Term
| what is membrane potential with EPSP? |
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Definition
| it approaches threshold, so neuron is more easily stimulated |
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Term
| when does inhibitory postsynaptic potential (IPSP) occur? |
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Definition
| it neurotransmitter causes hyperpolarization of post-synaptic membrane, if Cl-1 flow into cell or if K+1 flow out of cell |
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Term
| what is membrane potential with IPSP? |
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Definition
| moves away from threshold, so neuron is harded to stimulate |
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Term
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Definition
| all postsynaptic potentials are added together and whether post-synaptic neuron fires depends on NET input of EPSP's and IPSP's |
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Term
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Definition
| it is too weak and short lived to depolarize membrane to threshold |
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Term
| where does a temporal summation occur? |
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Definition
| at single synapse because each EPSP is generated at such a short interval that previous EPSP hasn't decayed |
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Term
| consequences of temporal summation |
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Definition
| if enough EPSPs are generat to depolarize post-synaptic membrane to threshold, action potential is generated |
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Term
| when does spatial summation occur? |
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Definition
| when several pre-synaptic neurons generate EPSPs at the same time |
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Term
| consequences of spatial summation |
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Definition
| single synapse only allows small numbers of Na+1 into post-synaptics membrane, but if multiple synapses allow wnough Na+1 to enter and post-synaptic membrane is depolarized to threshold, action potential can be generated |
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Term
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Definition
| several neuron cooperate together to enhance effects on one onother |
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Term
| what is pre-synaptic inhibition? |
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Definition
| when one pre-synaptic neuron may supress another pre-synaptics neuron to halt transmission of nerve signal |
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Term
| GABA and presynaptic inhibition.. |
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Definition
| GABA may be released, which prevents pre-synaptic neuron from releasing neurotransmitter into synaptic cleft |
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Term
| neurotransmitter deficiencies [2] |
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Definition
-alzheimers disease
-parkinson disease |
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