Action potentials are generated along a neuron because __________. [Hint]

of cytoplasmic streaming within the neuron
depolarization of the membrane at one point causes an increase of permeability to sodium at the next point
they are pulled along by positive-negative attraction
the neuron cytoskeleton conducts electricity as long as an ion gradient is maintained by the sodium-potassium pump
of all of these factors

Since this is not my area of expertise, I searched Google under the key words "action potential neuron" to get these possible sources:

http://faculty.washington.edu/chudler/ap.html
http://en.wikipedia.org/wiki/Action_potential
http://www.bris.ac.uk/synaptic/public/basics_ch1_2.html
http://www.blackwellpublishing.com/matthews/channel.html

In the future, you can find the information you desire more quickly, if you use appropriate key words to do your own search. Also see http://hanlib.sou.edu/searchtools/.

I hope this helps. Thanks for asking.

The correct answer is: depolarization of the membrane at one point causes an increase of permeability to sodium at the next point.

To generate an action potential, the membrane potential of a neuron needs to reach a certain threshold, typically around -55mV. This is achieved through a process called depolarization. When a neuron is at rest, the membrane potential is relatively negative due to an unequal distribution of ions, with more sodium ions (Na+) outside the neuron and more potassium ions (K+) inside.

When a stimulus is received, it can cause the opening of voltage-gated sodium channels in a specific region of the neuron's membrane. This allows sodium ions to enter the neuron, leading to a depolarization of the membrane at that point. As the sodium ions enter, the positive charge inside the neuron increases, moving the membrane potential closer to 0mV.

Importantly, this depolarization spreads along the neuron due to a phenomenon called an action potential. The depolarization at one point opens voltage-gated sodium channels in the neighboring region of the neuron, causing sodium ions to enter and further depolarize the membrane. This creates a positive feedback loop that allows the action potential to propagate along the neuron.

So, the correct answer is that action potentials are generated along a neuron because depolarization of the membrane at one point causes an increase of permeability to sodium at the next point.