12475679
Description
Quiz by Rachel O' Flynn, updated more than 1 year ago
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Created by Rachel O' Flynn
about 6 years ago
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Question 1
Question
Which of the following statements are false
Answer
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Membrane permeability to Ca2+ is very high
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The membrane is not very permeable to K+ ions
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Permeability to Na+ is 20% that for K+
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The ease with which the ion passes through the membrane is referred to as conductivity (C)
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If the conductance for an ion increases, the ion will pass through the membrane and a current will flow
Question 2
Answer
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Positive
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negative
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positive
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positive
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positive
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positive
Question 3
Question
Which of the following statements are true?
Answer
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The resting membrane potential in contractile cells of the atria and ventricles is about -70mV
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The inside of the cell is positively charged in relation to the outside of the cell
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The resting membrane potential is primarily due to two things; the high concentration of potassium ions in the intracellular fluid and the high permeability of the cell membrane K+ ions as compared to other ions
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The resting membrane potential is close to the equilibrium potential for sodium
Question 4
Answer
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0
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1
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2
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3
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4
Question 5
Question
Which of the following are the events of phase 0 - upstroke
Answer
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Potential reaches threshold: –65 mV
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Membrane’s ionic permeability suddenly changes
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Cell rapidly depolarises and over shoots to a positive potential of +40mV
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At the threshold potential, voltage sensitive potassium channels open very quickly
Question 6
Question
The membrane potential does not reach the equilibrium potential of sodium because the outward [blank_start]potassium[blank_end] current is still flowing
Answer
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potassium
Question 7
Question
In early repolarisation why is the overshoot brief?
Answer
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Fast sodium channels that are self inactivating decreases conductance of sodium
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Fast potassium channels that are self inactivating decrease conductance of potassium
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Voltage sensitive sodium channels quickly close
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Voltage sensitive potassium channels quickly close
Question 8
Question
Within a couple of milliseconds the membrane voltage repolarises a few mV, owing to an outward current of
Answer
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Calcium ions
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potassium ions
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sodium ions
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