Term
Why is the resting membrane potential -65mV and not -95mV? |
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Definition
B/c it is easy to manipulate -65mV rather than -95mV |
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Term
How is an action potential triggered in a neuron? |
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Definition
1) Start of the action potential 2)Trigger zone/Axon hillock 3) Voltage gated Na+ channel 4) All or none principle |
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Term
What is the trigger zone? |
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Definition
Axon hillock- Where graded potentials come together to form an IPSP or EPSP. |
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Term
NT can open ion channel in Pre-synaptic? |
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Definition
False, NT's open ion channels in dendrites and cell body (post synaptic cell) not pre-synaptic |
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Term
What does EPSP's and IPSP's stand for? |
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Definition
EPSP= Excitatory postsynaptic Potential
IPSP= Inhibitory postsynaptic potential |
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Term
Where are the EPSP's and IPSP's summed? |
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Definition
Axon Hillock/Trigger zone |
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Term
Define Graded potentials? |
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Definition
Potentials generated at dendrites and cell body is graded and can decay over distance.
vs. Action potential are generated at axon hillock/trigger zone and have an "All or none effect" (dont decay over distance) |
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Term
T/F: The decay of graded potential is exponential? |
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Definition
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Term
What determines if an action potential will occur? |
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Definition
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Term
What are the two types of graded potential summation? |
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Definition
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Term
What is the difference between Spatial and Temporal summation? |
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Definition
1) Temporal summation are PSP's (postsynaptic potentials) from one presynaptic neuron. The PSP's are sepreated by time and are fired rapidly one after the other and are summated to reach the threshold to cause an Action potential (AP)
2) Spation summation are PSP's from multiple presynaptic neurons (on the same post-synaptic soma) firing IPSP's or EPSP's and the soma summates these to form an AP. |
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Term
What do they mean by "all or none" when referring to AP? |
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Definition
Means that the potential will fire regardless after the threshold is reached (At axon hilloc) and will not decay over time. |
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Term
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Definition
Rapid change in membrane potential from - to + and back to -; All of none |
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Term
What are the 4 stages of an AP? |
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Definition
1) Resting stage 2) Threshold 3) Depolarization 4) Repolarization |
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Term
What channels are active in the resting stage? |
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Definition
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Term
What channels are active during the Depolarization phase of action potential? |
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Definition
1) Voltage gated Na+ channels |
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Term
What channels are active during the Repolarization of AP? |
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Definition
Voltage gated K+ channels |
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Term
When does the VG Na+ and VG K+ channel open? |
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Definition
They both respond at the same time to depolarization but K+ channels have SLOW ACTIVATION, so they don't actually have K+ go down the gradient till +35mV |
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Term
Why don't AP's decay over time? |
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Definition
Depolarization of the axon at one point causes voltage-gated Na+ channels to open ahead of this point. Thus the AP migrates down the axon. |
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Term
List 3 Amino Acid NT and their fxn? |
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Definition
1) Glutamate- Excitatory NT of brain
2) GABA- Inhibitory NT of brain
3)Glycine- Inhibitory NT of spine |
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Term
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Definition
1) Serotonin (5-HT) 2)Histamine 3)Dopamine (DA) 4)Norepinehprine (NE) 5) Epinephrine (E) |
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Term
Name a purine derivative NT? |
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Definition
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Term
Name 3 types of peptide NT released by the Hypothalamus? |
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Definition
1) Thyrotropin releasing hormone 2) Lutenizing hormone releasing hormone 3) Somatostatin |
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Term
Name 7 peptide NT released by the Pituatary? |
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Definition
1) Adrenocortico tropic hormone-ACTH 2)Prolactin 3)Lutenizing Hormone 4) Thyrotropin 5) Growth Hormone 6)Vasopressin 7) Oxytocin |
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Term
What kind of NT are endorphins? |
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Definition
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Term
What are 2 types of Peptide NT that are endorphins? |
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Definition
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Term
Name 3 'other' types of peptide NT? |
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Definition
Substance P, Andgiotensin II, Bradykinin |
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Term
Where are peptide NT made? |
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Definition
In the cell body of neuron (and travel all the way down in the terminus of neuron)
-EX. Thyrotropin Hormone, Lutenizing Hormone, Bradykinin, ACTH...etc, |
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Term
Where are small NT (Dopamine, 5-HT, ATP, Histamine...etc) made? |
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Definition
Small NT are made in axon terminal? |
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Term
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Definition
Precursor molecule (tryptophan) with the aid of a synthetic enzyme turns into a NT molecule (seratonin) which gets packed into vesicles with the help of Transporter proteins. |
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Term
Name 2 gas NT and where are they made? |
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Definition
1) Nitric Oxide (NO) 2) Carbon monoxide (CO)
- Gas NT are not made in cell body or the axon terminal they diffuse right thru the neuron |
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Term
Name 2 endocannabinoid NT? |
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Definition
1) Anandamide 2) Arachidonyl glycerol |
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Term
How effect does THC have in the neuron? |
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Definition
THC causes the depression of glutamate (excitatory NT of brain) and decrease the amount of Ca2+ released. So THC (comes from weed) slows neural transmission in brain and slows movement |
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Term
Name the neuron that releases 1) Ach 2) DA 3)NE 4)Glu 5) GABA 6)Peptide |
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Definition
1) Cholinergic neuron 2) Dopaminergic 3) noradrenergic 4) Glutamatergic 5) GABAergic 6) peptidergic |
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Term
Name 3 types of NT receptors and give examples |
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Definition
1) Transmitter-gated ion channels (aka ionotropic receptors)- Example: Nicotinic receptor and GABA receptor
2) G-protein coupled receptors (aka metabotropic)- ex. Muscarinic receptor 3) Enzyme linked receptor (ex Tyrosine Kinase receptor) |
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Term
Give two examples of Ach receptors? |
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Definition
1) Nicotinic Receptor (Ionotropic receptor) 2) Muscuranic Receptor (Metabatropic receptor) |
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Term
On the Nicotinic and muscarinic receptors, note what 1) NT acts on it 2) Agonists 3)Antagonists |
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Definition
Nicotinic receptor (Ionotropic receptors)- 1) Ach 2)Ach and Nicotine 3)Curare
Muscarinic (Metabotropic receptor)- 1) Ach 2)Ach and Muscarine 3) Atropine |
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Term
What type of NT receptor is the GABA receptor? What kind of ion channel is GABA? |
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Definition
Ionotropic receptor/ Transmitter-gated ion channels and it is a chloride ion channel |
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Term
What are the 5 things that can bind (agonist) to a GABA receptor? |
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Definition
1) GABA NT 2) Benzodiazapine 3) Barbiturate 4) Steriod 5) Propofol |
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Term
Describe the mechanism of giving a patient propofol? |
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Definition
1) Propofol bind to the GABA receptors (Propofol is an agonist for GABA) 2) GABA receptors activate/open and allow Cl- to go down their gradient (inside the cell) which causes the Vm to become more negative (hyperpolarize) thus creating an IPSP 3) The IPSP summate and DO NOT reach threshold and thus do not creat an AP, thus no neuronal transmission is made in the brain (since GABA receptors are found in the brain) |
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Term
What happend when GABA and a pentobarbital is released as NT on the GABA receptors? |
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Definition
Giving the barbituate adittionally (since GABA NT is naturally occuring in the brain) opens the channel more frequently thus causing more IPSP's |
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Term
What are three targets of the activated metabotropic receptors? |
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Definition
1) Enzymes (ex. PLC, Adenyl Cyclase) 2) ion channels 3) Gene transcription |
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Term
What is the fxn of Adenyl cyclase and what is it activated by? |
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Definition
1) Fxn- to make ATP to (secondary messenger molecule) cAMP of GTP to cGMP
2)Activated by diffused G-protein
- Adenyl cyclase is an enzyme that is a targeted by activated G-proteins |
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Term
What is the fxn of PLC and what activates it? |
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Definition
1) Fxn- to make IP3, membrane phospholipid, and DAG by splitting PLC (Phospholipase-C) 2) PLC is activated by Acitvated diffused g-protein. |
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Term
What type of NT receptor are protein kinases? |
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Definition
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Term
What is Protein kinase fxn? and what are its indirect effectors? |
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Definition
Fxn to P-late protein, which changes its conformotion,thus changing the protein's fxn, and the P-lated protein open's ion channels or alters enzyme function. |
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Term
Name a fast, short acting fast synaptic potential and a Slow synaptic potentials and has long term effects NT receptor? |
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Definition
1) Transmitter gated ion channels (aka ionotropic channels) - Ex. GABA receptors and Nicotinic receptor
2) G-protein coupled receptor (aka metabotropic receptor)- Ex. Muscarinic |
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Term
What are 3 ways to terminate a transmitter action? and Give description |
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Definition
1) Diffusion- NT can diffuse out of the synaptic cleft
2) Breakdown- Enzyme inactivat NT's (Ex. Actelycholinesterase) 3) Re-uptake- NT can be returned to axon terminals for reuse or transported into glial cells |
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Term
In Layman terms describe Potentiation of synapses? |
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Definition
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Term
How does potentiation of synapses work? |
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Definition
1) Increases the release of NT from presynaptic neuron which,
2) Inc. the response in the postsynaptic neuron |
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Term
during Potentiation of synapses, there is an inc. of NT released but what else can it cause? |
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Definition
Depression of communication |
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Term
Describe synaptic fatigue? |
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Definition
After many, many AP eventually the NT stored in vesicles is depleted. |
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Term
What can clinically happen in a synaptic fatigue? |
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Definition
Siezure- NT storage depleted |
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