Question

Action potentials propagate as invariant (stereotyped) signals. What does the word "invariant" in this statement mean?
a. Action potential are cool
b. Action potentials are all or nothing signals
c. Action potentials vary depending on the stimulus
d. Action potentials are sometimes fast and sometimes slow

Answer 1

Answer:

The correct answer to the question: What does the word "invariant" in this statement mean?, would be: B: Action potentials are all or nothing signals.

Explanation:

An action potential is almost like the way that cells, especially neural cells communicate and contact one another. In order for this potential to happen, certain ionic changes must happen both in and outside of cell membranes, which charges the cell until it surpasses a certain threshold and fires out signals, both in, and out of it. One characteristic of action potentials, however, is that they are an "all or nothing" type, which means, that once initiated, an action potential will reach threshold and then fire, whatever else happens. Their intensity doesn´t change and once started it cannot be stopped. This is what the word invariant means, these signals will happen once the stimulus has initiated them, but they will not change in nature, or course, regardless of further stimulus. What stimulus does is no initiate the same potential but in more cells than the original one, but each individual cell will undergo action potential activities with, or without, more, or less, stimulus.

Answer 2

In the neuron membrane, the shift of the potential from negative to positive is called an action potential. Invariant means action potentials are all or nothing signals.

What is an Action potential?

The electrical impulses in the body that temporarily shift the negative and the positive potential of the nerve cell membrane are called the action potential. This is a method of the sending and the receiving of the signals in the cells.

The action potential occurs in the presence of certain ionic charges in and out of the membrane. They are all or nothing as when the action is started then the threshold will be reached no matter the situation.

When the action potential is started they cannot be stopped and their intensity does not get affected. In the presence of the stimuli, the action potential will be experienced by all of the cells.

Therefore, option b. they are all or nothing signals.

Learn more about action potentials here:

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