PHC 7010 Exam 2 Neuropharmacology Questions and Answers.
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PHC 7010
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PHC 7010
PHC7010Exam2NeuropharmacologyQuestions and
Answers.
Lecture 1: Principles of Cellular Excitability and Electrochemical Transmission - Correct
Answer
How is an electrical circuit the same as hydraulic system? - Correct Answer Voltage=
pressure
Current= Water flow
Resistance= Tap
What is Ohm'...
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PHC 7010 Exam 2 Neuropharmacology Questions and
Answers.
Lecture 1: Principles of Cellular Excitability and Electrochemical Transmission - Correct
Answer
How is an electrical circuit the same as hydraulic system? - Correct Answer Voltage=
pressure
Current= Water flow
Resistance= Tap
What is Ohm's Law? - Correct Answer V = IR. Relationship between voltage, current and
resistance.
What is conductance? - Correct Answer Reciprocal of resistance. R=1/g
g= conductance
What is current? - Correct Answer I=gV. Straight line on current vs potential graph.
What kind of membrane potential do cells have? Why? - Correct Answer Negative. More
negative ions on inside than outside. Vm= Vin-Vout.
What is the capacitor in a cell? - Correct Answer Plasma membrane, it stores electrical
energy.
What is resistor in cell membrane? - Correct Answer Ion Channel.
What do ions in solution have? - Correct Answer Hydration shell
What does removing hydration shell do to ions? - Correct Answer Makes it energetically
unfavorable and separates ions across lipid bilayer
What creates the negative membrane potential of cell? - Correct Answer Na+/K+ ATPase.
3Na+ leave for every 2k+ entering.
,How do ion channels catalyze translocation of ions across membrane? - Correct Answer
They lower the energy barrier to remove hydration shell. They makes this energetically
viable by replacing hydration shell surrounding ion with charged residues within channel
lumen.
What makes it possible for selectivity filter to select between sodium and potassium? -
Correct Answer The precise spatial coordination of residues that replaces hydration shell
(this is for potassium or sodium channels, not Na+/K+ pump). Makes it specific for one ion.
Which ion contributes most to the resting membrane potential? - Correct Answer K+
moves down its concentration gradient (efflux)
When does K+ efflux stop? - Correct Answer Concentration gradient pulling K+ outward is
balanced by electrical force pulling K+ in (because cell is negative, it pulls K+ in)
What is the Nerst equation used for? - Correct Answer Calculates equilibrium potential for
ions.
Why do we need to use Goldman- Hodgkin Katz equation? - Correct Answer Membrane
potential is calculated by contributions from multiple ions, not just one (or else we would
use nerst equation)
How do ions contribute to cell membrane potential? - Correct Answer Concentration
gradient across membrane and membrane permeability
What is permeability of ions? - Correct Answer Ease with which ions cross membrane
(how many ion channels are open)
How is membrane potential determined? - Correct Answer Nernst potential and their
relative permeability, goldman-hodgkin Katz equation.
,What happens to membrane potential whenever ion selective channel opens? - Correct
Answer The membrane potential shifts towards nernst potential for that ion
What is outside mV of cell? - Correct Answer 0 and inside is negative
What happens when depolarization crosses voltage threshold? - Correct Answer If it
crosses -50mV, it elicits AP
What channels are highly diverse, and structurally related? - Correct Answer Ion
Channels (can open or close)
What structural feature allow ion channels to sense voltage? - Correct Answer 4
transmembrane helices (S1, S2, S3, S4)
What is the structure of voltage gated ion channel? - Correct Answer S1-S4: Voltage
sensor
S5-S6: Ion flow
How does paddle work in ion channels? - Correct Answer Transmembrane helices (S3,
S4) translocate in response to changes in membrane potential. Channel open is
probabilistic and depends on voltage.
What is macroscopic current dependent upon in channel? - Correct Answer Voltage
dependent
How do Na+ channels open? - Correct Answer Open then inactivate
What is the AP ion permeability like? - Correct Answer Permeable to Na+ then DELAYED
K+ permeability
(conductance over time graph)
What is increase in sodium conductance a directly result of? - Correct Answer Voltage
dependence of sodium channels
, Why is AP transient, all or none depolarization? - Correct Answer Opening of Na+
channels triggers further depolarization, by opening more Na+ channels.
Why is AP depolarization transient? - Correct Answer Sodium Channels inactivate
What is repolarization of AP? - Correct Answer Delayed opening of K+ channels
How do Na+ Channels contribute to refractory period? - Correct Answer Sodium channel
inactivation make areas unexcitable immediately after an AP. This makes AP travel
unidirectionally.
How does wave of depolarization (AP) travel along axon? - Correct Answer Current flow
depolarizes nearby membranes
Are synapses always made from presynaptic neurons to post synaptic neuron? - Correct
Answer Generally yes, but not always
What does synapse transform? - Correct Answer Transforms electrical signal (AP) into
chemical signal (release of neurotransmitter)
What is presynaptic terminal highly enriched in? - Correct Answer Synaptic vesicle
(containing neurotransmitter)
What happens when AP reaches presynaptic terminal? - Correct Answer Open voltage
dependent calcium channels, this triggers vesicle of neurotransmitter to fuse with plasma
membrane and release neurotransmitter into synaptic cleft (specialized form of
exocytosis)
What does vesicle fusion involve? - Correct Answer Snare proteins (Vsnare on synaptic
vesicle joins with Tsnare on pre-synaptic plasma membrane). Synaptotagmin acts as
calcium sensor.
What happens after vesicle fusion? - Correct Answer Neurotransmitter diffuses across
synaptic cleft and binds ionotropic and metabotropic receptors to elicit post synaptic
reponse.
Lecture 2: Principles of Nervous System Physiology and Pharmacology - Correct Answer
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