Final answer:
Action potentials are always the same strength once initiated, while graded potentials can vary. Action potentials occur at the Nodes of Ranvier in myelinated neurons due to the concentration of ion channels.
Step-by-step explanation:
The action potential is always the same strength. Graded potentials can vary in strength, but action potentials, once triggered, maintain a consistent magnitude.
Electrical gradients are crucial for both resting potential and action potential in neurons. The resting potential is a stable, negative charge of a neuron's membrane at rest, usually around -70mV. It's the foundation upon which action potentials are built.
Action potentials occur when a neuron sends information down an axon, away from the cell body. They are all-or-nothing events that occur when the membrane potential reaches a certain threshold level. Unlike graded potentials, which are changes in membrane potential that are proportional to the intensity of the stimulus, action potentials are always of the same magnitude due to the regenerative nature of the voltage-gated ion channels. Once initiated, they travel down the axon without decreasing in strength.
In myelinated axons, action potentials occur at the Nodes of Ranvier. This is because myelination increases the speed of transmission along an axon and the nodes are the points where ion channels are concentrated and capable of generating an action potential.