They are called neurons.
The nervous system. Horse Isle Quiz Answer: Neurons
The nervous system coordinates all body processes. The nerves carry electrochemical signals that transmit messages from one part of the body to another.
battery
A reference electrode is a stable electrochemical electrode with a known and constant electrode potential. It is used as a comparison point in electrochemical measurements to determine the potential of another electrode in a cell. Reference electrodes help provide accurate and reliable measurements in various electrochemical processes.
A telegraph is a device for sending messages ("graph") over a distance ("tele"). Smoke signals sent by Native Americans qualify under this definition. So does the use of flags or signal fires. An electrochemical telegraph suggests that an electrochemical device, like an electrochemical cell or set of cells -- a battery -- is used to power up a system that transmits those messages. By making and breaking an electrical circuit with a telegraph key, a solenoid on the other end can be made to "click" and be heard. All that is required is a system of "code" to transmit characters from one point to another down a telegraph wire between the key and the solenoid. The battery provides the power. By using that same electrochemical source, a light could be powered up using the key. With the light and the same code used in sending messages over a wire, an individual could communicate between two points without a wire. Ships at sea could communicate with that light (though they usually use ship's power instead of a battery), or two scouts on a camping trip could communicate silently across a broad valley using flashlights.
Rechargeable battery or electrochemical battery.
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I think the answer you're looking for here is nervous tissue which carries action potentials, or nervous impulses, between the tissues and are central nervous system. However, from another point of view you could also consider the cardiovascular system as carrying hormonal messages throughout the body.
While a neural signal is chemically conveyed from one neuron to another by neurotransmitters, the electro-chemical neural impulse, which happens in the axon when the neuron fires, is called an action potential.
Carrying.
Neurotransmitters are chemicals released across a synaspe from one nerve to another in order to send an electrochemical message.
Another word for carrying is "transporting." Other synonyms include "conveying," "bearing," and "hauling," depending on the context in which it is used.