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Physiology I

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Cell membrane potential and homeostasis questions
ivenkat
Quiz by ivenkat, updated more than 1 year ago
ivenkat
Created by ivenkat over 9 years ago
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Resource summary

Question 1

Question
All of the following are true except
Answer
  • The role of negative feedback system is to bring it back to Set point
  • The role of a positive feedback is all about destabilizing the system and amplifying the signal
  • Blood clotting, uterine contractions in response to oxytocin are examples of positive feedback
  • None of the above

Question 2

Question
All of the following are true about diffusion is dependent
Answer
  • It is dependent on the cross sectional area thru which the flow of solute is measured
  • The difference in solute concentration between regions
  • The distance (or thickness) between regions A and B
  • The lipid solubility of the solute
  • The difference in solvent concentration between regions

Question 3

Question
All of the following are true about diffusion except?
Answer
  • IF you increase the molecular size the Net flux increases
  • The more the solubility in lipid the faster that molecule diffuses (like CO2 vs O2)
  • The thinner the membrane the faster the net flux
  • larger the concentration difference the faster the net flux

Question 4

Question
In osmosis there is net movement (passive) of Water across a semi permeable membrane
Answer
  • True
  • False

Question 5

Question
When thinking about Tonicity, think ONLY about NaCL
Answer
  • True
  • False

Question 6

Question
The following are the sequence of events if you add water to ECF - all are true except?
Answer
  • ECF will be diluted compared to ICF
  • Water will move from ECF to ICF
  • Increase in ECF volume and decrease in ICF volume
  • Once it reaches equilibrium both ECF and ICF will have the same osmolarity

Question 7

Question
Protein Mediated Transport rate will be faster with increase in substrate concentration
Answer
  • True
  • False

Question 8

Question
All of the following about Cardiac glycosides (digitalis) are true except?
Answer
  • Blocks NaK ATPase
  • Increase the ICF concentration of Na and decrease the ICF concentration of K
  • This will increase the chemical gradient for Na to come into the cell
  • Ca antitransporter slows down which increases the ICF conc of Ca thereby increasing contractility

Question 9

Question
All of the following are true about RMP except
Answer
  • When RMP = -110 mv inside is more negative --> draws K into the cell and it is hyperpolarized enough to have more K coming in than leaving, despite that being against it's conc gradient
  • When RMP = +30 inside is more positive than the outside -->both the electrical and chemical gradient is pushing K out of the cell
  • none of the above

Question 10

Question
Generation of resting membrane potential - all the following true except?
Answer
  • if only K is permeable, Equilibrium potential for K will determine the RMP and it will be -94mV
  • If only Na is permeable then the RMP would be +60mV (which is the equilibrium potential for Na)
  • When there are 2 ions moving (back of forth thru the membrane) the RMP will be determined by the ion with the greater number of leaky (non-gated) channels
  • none of the above

Question 11

Question
Increasing the ECF concentration of NA makes the RMP more positive
Answer
  • True
  • False

Question 12

Question
If you make the membrane even more permeable to K - then the membrane will be hyperpolarized
Answer
  • True
  • False

Question 13

Question
All of the following are true about Electronic Potentials except?
Answer
  • Subthreshold depolarizing events
  • Chemical, mechanical stimuli
  • Polarity inside positive
  • Does not propagate
  • No refractory period

Question 14

Question
All are true about Action potential except?
Answer
  • All or nothing event
  • Chemical or mechanical stimuli
  • Polarity with inside positive
  • Propogates
  • Refractory period (including Absolute refractory period)

Question 15

Question
All of the following are true except?
Answer
  • At rest - membrane is most permeable to Na
  • At Threshold - voltage-gated Na channels open
  • Rising phase and overshoot - membrane becomes so depolarized that it overshoots and is reversed in polarity
  • At or near the peak the Na permeability begins to decrease and K permeability through voltage-gated K channels increase (Both channels open in response to hitting Threshold, just Na open much faster)
  • Repolarization - Na voltage gated channels have started closing and voltage gated channels are opening
  • After hyperpolarization - voltage gated K channels are still open but they will gradually close at this point

Question 16

Question
TEA (tetra ethyl ammonium)
Answer
  • Block K current
  • Repolarization is affected
  • You can still get an AP (action potential) with this
  • all of the above are correct

Question 17

Question
TTX (Tetrotoxin) and Saxitoxin (STX)
Answer
  • Block Na voltage gated channels
  • Affects repolarization
  • cannot trigger an AP

Question 18

Question
All of the following about AP are true except?
Answer
  • AP is initiated at axon hillock - where there are the greatest number of voltage-sensitive gates are located
  • Nodes of Ranvier will increase the propagation of the AP
  • Inhibitory Post synaptic mediators like GABA will activate Cl- channels which causes and influx of Cl- which in turn will hyperpolarize the cell
  • none of the above

Question 19

Question
the slower the Time Constant the greater the Propagation Velocity
Answer
  • True
  • False

Question 20

Question
The greater the Length(space) Constant the shorter the membrane will stay depolarized
Answer
  • True
  • False

Question 21

Question
Electrical Synapse has Bidirectional flow whereas a Chemical synapse has Unidirectional flow
Answer
  • True
  • False

Question 22

Question
The Following is the sequence of events at the synapse
Answer
  • An AP arrives at the presynaptic terminal
  • Voltage-gated Ca channels open and Ca enters the cell
  • This Ca triggers the fusion of synaptic vesicle with the post synaptic membrane
  • NTM (neuro transmitter) diffuse across the synaptic cleft and bind to the specific receptors on the post synaptic cell
  • Bound receptors will activate the post synaptic cell and the NTM breaks down and is taken up by the pre synaptic terminal or other cells or diffuses away from the synapse

Question 23

Question
All of the following about the toxins are true except?
Answer
  • Conotoxin will inhibit the release of NTM
  • Tubocurarine and Bungotoxin block the AcH receptors
  • Tetanus toxin cleaves synaptobrevin - prevents the release of GABA - causing spastic paralysis
  • Botulin cleaves synaptobrevin - prevents the release of Ach - flaccid paralysis
  • none of the above

Question 24

Question
Metabotropic receptor acts through a secondary messenger
Answer
  • True
  • False

Question 25

Question
Inhibitory Postsynaptic Potentials (IPSP) act either by Opening of Cl- or K+ channels
Answer
  • True
  • False

Question 26

Question
NE is the primary excitatory transmitter for postganglionic neurons of the sympathetic nervous system
Answer
  • True
  • False

Question 27

Question
Degeneration of Dopaminergic neurons in substantia Nigra leads to Parkinson's disease
Answer
  • True
  • False

Question 28

Question
Dopamine can be used as treatment for Parkinson's disease
Answer
  • True
  • False

Question 29

Question
All of the following are inhibitory NTMs except
Answer
  • Glutamate
  • GABA
  • Glycine
  • All of the above

Question 30

Question
Nicotinic receptors are Metabotropic whereas Muscarinic receptors are Ionotrophic
Answer
  • True
  • False

Question 31

Question
NMDA receptor is specifically excitatory glutamate receptor for which Glycine must also be bound for the ion channel to open
Answer
  • True
  • False

Question 32

Question
Temporal summation occurs when consecutive synaptic potentials arrive at the postsynaptic cell and add together
Answer
  • True
  • False

Question 33

Question
PCP(phencyclidine) is the antagonist for NMDA receptor
Answer
  • True
  • False
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