Nerve cells, or neurons, have a basic tree-like structure, which allows them to communicate with other nerve cells. Branch-like dendrites extend from the cell body (i.e. soma) and receive electrochemical signals from other cells. The long, thin axon endings—terminal buttons—extend from the other end of the soma. If the positively-charged signals received into the cell from the dendrites exceed the cell’s normally negative charge, then the axon allows the excess positive ions to travel down it to the terminal buttons, which in turn send neurotransmitters into the gap (i.e. synapse) between them and other cell’s dendrites. The myelin sheath does not itself relay signals, but rather is a natural lipid insulation on the axons of some cells. 

Sodium and potassium are vital components associated with neural electrical transmissions. When it is at rest, a neuron is surrounded by a positive charge due to sodium and maintains an internally negative charge with potassium. When the neuron depolarizes, there is an influx of sodium into the cell. Upon repolarization, there is a potassium efflux where the neuron is restored to its original resting charges.

The correct answer is antagonist. An antagonist is any chemical that prevents a neurotransmitter from binding to its receptor site. Recall that a neurotransmitter is simply any chemical in the brain that enables the transmission of signals between neurons via synapses. Contrastingly, an agonist is any chemical that mimics the shape of a neurotransmitter well enough that it can bind to that neurotransmitter's receptor and stimulate the receptor just as if the neurotransmitter itself was binding to it. A so-called reuptake agent is not a real chemical classification, but the reuptake mechanism is an important aspect of neurotransmission. Reuptake refers to the process by which the presynaptic neuron reabsorbs its released neurotransmitter after the neurotransmitter has done its job by binding to the postsynaptic neuron.

Information enters the neuron through dendrites, the branch-like extensions which carry signals to the cell body (soma). When an action potential occurs, its signal will propagate down the axon of the cell, culminating in the release of neurotransmitters into the synapse from the terminal buttons. These neurotransmitters will cross the synaptic cleft in mere milliseconds, and bind to the receptor sites on the adjacent neuron's dendrites. This process leads to communication between neurons.

An action potential occurs when a neuron transmits an electrical charge down its axon, which terminates in the release of chemical signals in the form of neurotransmitters. These neurotransmitters communicate with other neurons, allowing for the flow of information between the cells of the nervous system. The chemical compounds emitted by neurons as a result of action potential are known as neurotransmitters. Though the release and binding of neurotransmitters to receptor sites on dendrites may result in either inhibitory or excitatory responses, they themselves are referred to as action potentials. Although an action potential is able to occur by way of a maintained electrical gradient within the neuron, it is not correctly described as 'the latent energy of a system'. Likewise, an action potential is not a behavioral predisposition.

Neurons transmit electrical signals between one another, which allows for the communication of incoming stimuli from sensory receptors with the brain, communication of internal states of the body, communication between the brain and muscles to coordinate movement, and communication between the many cells of the brain to allow for the complex array of processes that form the basis for our everyday lives. Although neurons in the visual centers of the brain will indeed play a role in processing color information, at the level of the retina this information is derived from the the cones in photoreceptor cells, and subsequently communicated to the brain via the optic nerves. Neurons will communicate messages between the brain and glands of the body, but they themselves are not responsible for the production of enzymes. Neurons do not serve as energy stores for the body.

Action potentials created by neural impulses are described as being "all or nothing" because the cell either gains sufficient stimulation to release an action potential, or it does not. Once the minimum threshold for excitation is reached, an action potential will be triggered regardless of further stimulation, and no signal will be weaker or stronger than any other. That being said, continued stimulation of a neuron may lead to continued firing of action potentials, which may trigger a stronger or enduring response over time. At the scale of the individual action potential; however, the activity of the neuron may be considered as either a value of 0 (i.e. no action potential), or 1 (i.e. action potential). No decimals are used in this measure.

The membrane potential of a neuron rests at -70mV when not receiving stimulation. After receiving sufficient stimulation to pass the threshold potential of -55mV, the action potential triggers, rapidly increasing the membrane potential to a peak of 40mV, before dropping to -90mV during the refractory period, and finally returning to a resting potential of -70mV after the action potential has completed. This entire process can take place in as little as 4 milliseconds. 

All animal cells are polarized, because they maintain a difference in voltage between their interiors and their surroundings. This is measured at the cell membranes and known as a membrane potential. The resting potential of a neuron is the value its membrane potential keeps as long as it is not receiving stimulation or undergoing an action potential. In a typical neuron, this resting potential is -70 millivolts (mV). This value does not reflect the average time a neuron spends at rest. The stage of hyperpolarization of a neuron is known as the refractory period. Although the resting potential of a neuron implicates its chemical state and contributes to its probability of firing an action potential, neither of these statements are correct definitions for the term.

A stimulus begins the propagation of the action potential, and channels open to admit sodium into the cell. This leads to a rapid depolarization, as the positively charged sodium ions rush in to balance out the negative resting potential of the neuron (-70mV). At the peak of depolarization, the interior of the cell becomes more positively charged than the exterior. Repolarization subsequently occurs, as the sodium channels are closed, and potassium channels opened in their stead, allowing positively charged potassium ions to exit the cell, restoring the negative membrane potential of the neuron. The refractory period ensues. After the opening and closing of the sodium channels, they are briefly set in an inactive state, and cannot be opened again until the membrane resting potential is restored. During this time, sodium and potassium pumps return sodium to the exterior and potassium to the interior of the cell. As it is impossible for any region of the cell to depolarize during this stage, action potentials may not occur and the neuron is at rest.