action potential

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sarahh
sarahh's picture
action potential

Dear members:

I am a student in health sciences and I am confused about the action potential concept (see nervous system). Please let me know if I got the right answers.

I have 3 multiple-choice questions that I need help with:

Which is the correct sequence of events that follows a threshold potential:
1.the membrane becomes depolarized
2.sodium channels open and sodium ions diffuse inward
3.the membrane becomes repolarized
4.potassium channels open and potassium ions diffuse outward while sodium is actively transported out of the cell
A)3,2,4,1
B)2,1,4,3
C)2,1,3,4
D)1,2,4,3
E)4,1,3,2

My answer is C, but not sure because the questions refers to the sequence of events THAT FOLLOWS A THRESHOLD POTENTIAL. I am debating between C and D.

Second questions is:

An action potential:
A)is essential for impulse propagation
B)involves the influx of negative ions to depolarize the membrane
C)involves the outflux of negative ions to depolarize the membrane
D)involves the outflux of positive
ions to depolarize the membrane
E)is initiated by potassium ion movements

My answer is A

Match the following:

1.Period when the interior of the cell becomes less negative due to an influx of sodium ions

2.Term a nerve impulse when transmitted

A)action potential
B)saltatory conduction
C)repolarization
D)depolarizarion

My answer is 1.D and 2.A

I really appreciate your help.

Sarah

Guy Sovak
Guy Sovak's picture
Hi

Hi
I wouldnt tell you the right answers but I will give you two links that would clrify the answers.
http://www.tvdsb.on.ca/westmin/science/sbioac/homeo/action.htm
and here is an animation
http://www.blackwellpublishing.com/matthews/channel.html
hope it helped
if not write

baffa
baffa's picture
your answers to the first

your answers to the first question were not correct, the correct answer is B