Posted by Sarah on Saturday, December 2, 2006 at 4:46pm.
I am a little confused about the action potential concept (see nervous system)
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
My answer is C, but not sure because the questions refers to the sequence of events THAT FOLLOWS A THRESHOLD POTENTIAL. The correct answer could be 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
My answer is 1.D and 2.A
Thank you for your help.
I think if you read the following 2 sites it will help you a lot.
Yes, after you read the site mentioned by Lance, you should understand that your answer to the first question is not correct. If you are still unsure why, please repost!
Thank you Dan.
After visiting the first website, I am changing the answer to D. So, the explanation is that the cell membrane becomes depolarized first and then Na channels opens for the positive ions to difusse inside?
Please let me know if my understanding is correct.
The sodium channels open, and sodium goes in. This causes DEPOLARIZATION. Then, the potassium channels open, and potassium comes out. This causes REPOLARIZATION (cell goes back to its resting state).
So, the actual order is....2, 1, 4, 3.
Do you see that?
Answer this Question
Psychology - Your brain has instructed your muscles to move so an oncoming ...
human anatomy and physiology - cells are the basic unit of life based on the ...
anatomy & physiology - the portion of the nervous system that controls ...
Biology - "Emma has difficulty sleeping. Her doctor prescribes Deflex. Deflex ...
science - please help me in science i don`t now what is the answer of my ...
psychology - Mario gets out of bed in the morning,and without thinking about it...
Psychology/Science - I am doing a powerpoint presentation about neurons. I need ...
Nervous System - What are the important things about the nervous system?
anatomy and physiology II - Define PNS Peripheral Nervous System? = contains ...
Health - The portion of the nervous system that controls involuntary activities ...