How do chemical and electrical communications differ from one another? Specifically in regards to living organisms, i.e. humans.



It is my understanding that life forms use both chemical and electrical signals to communicate. I know chemistry is elements forming compounds through electrical bonds, and therefore electrical in a sense. But just because a copper wire has electrical bonds in its chemistry that’s not the same as when a current is sent through the wire.

What I’d like to understand is how do livings organism us chemical communication and electrical communication and how are they different?

In depth responses are appreciated.

In: Biology

Very good question. The human body utilizes both chemical and electrical signaling extensively. One type of cell that uses both is prolific throughout your nervous system: the neuron.

The neuron uses chemical signalling via neurotransmitters. These in turn affect various gates and change the amount of “stuff” that’s let into the cell.

Now what you have to understand is that current fundamentally is just a movement of charged particles. Voltage is a difference in potential, so it is in turn a difference in concentration of these charged particles. Your body is full of these, and notably Na+ (Sodium) and K+ (Potassium) are let in when a neuron is ready to send out a signal, or action potential.

So, a neurotransmitter is a chemical, which opens a gate in a cell. This gate then lets in ions, which are sitting in the fluid around the cell, thus generating a current as they rush in, and changing the voltage inside the cell (the difference in charged particles from the outside to the inside). Once this voltage hits a certain amount, the neuron releases an action potential, which is essentially a rapid rise in voltage across the cell membrane as it lets in more and more ions as the sodium channels are opened up. This current is carried along the neuron’s body, and propagates through its axon. Propagation essentially consists of a series of cell membranes being charged and depolarizing as the ions travel through, changing their voltage.

So to summarize, at the end of the day electricity is just created by a movement of ions. In the human body, this is regulated through chemical processes. I have to leave now, so I had to hurry up this response, but I’ll look to clarify it later. Feel free to ask any questions!

Cant precisely answer what the difference is biologically, as in how our body interprets them. But i can explain the difference between a chemical bond (molecular bond) and an electric current. Hoping im not breaking any rules here now, ill veer of eli5 sincr you asked for an indepth response.

So an atom is made up out of three things.

-Protons, with a postive charge.

-Electrons, with a negative charge.

-Neutrons, with a neutral charge.

The core (nucleus) of the atom consists of the protons and the neutrons. The protons decide what element the atom is. (Element=single atom, not molecule)Hydrogen will always have 1 proton, Helium always 2, Carbon always 6 and so on.

The Neutrons decide the isotope of the element. There can be different amount of neutrons in an element. But regarding this topic, its not so necessary to talk about.

The electrons are in the shells around the nucleus. This is where all the chemical reactions happen. By default, an element has as many protons as neutrons, so it has a neutral charge. Hydrogen with one proton, has 1 electron. Helium with 2 protons, has 2 electrons, and so on.

To figure out how chemical reactions happen, we need to figure out what exactly happens to the electrons in a molecular bond.

So all elements want to achieve whats called a “Noble Gas Structure”. This means that they want their outer shell to be completely full. And it is this desire for a full outer shell of electrons (Valence Shell) that drives chemical reactions.

The noble gases all have full Valence Shells, so they are not reactive. They do not bond with othet elements.

so there are two ways to achieve a full outer shell, you can either fill it by grabbing electrons, or drain it by giving electrons away. If you give away all the electrons in your outer shell, the shell just below it is now the outermost shell. And its also full.

So, elements that need just a few electrons to fill their shell will be looking to grab electrons, and elements that need alot of electrons to fill it, will be looking to give em away. This is how the groups are ordered in the periodic table.

From left to right, ignoring the metals, the amount of electrons any element needs to fill its shell drops by one. Left most elements, need to give away one electron to remove their outermost shell, and drop one tier.

The second to last group on the right side need only pick one electron up to fill their outer shell. The rightmost group are the noble gasses, and their shells are full.

The closer and atom is to a full shell, the more violently it will react. If two atoms need to change only one electron, and they are opposite. As in one wants to pick one up, and one wants to give it away, the reaction will be very violent.

So with that we can look at the two types of molecular bonds(Molecule = structure made up of two or more elements/atoms). Ionic Bonds and Covalent Bonds.

-Ionic Bonds

An Ion is an atom with an electric charge. The amount of electrons and protons are not balanced. This happens when something that really wants to give an electron away, meats something that really wants to pick it up (Electronegativity).

A good example of this are the two elements Sodium(Na) and Chloride(Cl).

Sodium needs to only give away one electron to drop its outer shell, and Chloride needs only one electron to fill its shell. When these two elements get close to eachother they react very violently by exploding. In that explosions one electron is moved from the Sodium to the Chloride. They have achievef noble gas structure

This should tell us they do not want to react any longer, but they are still going to form a bond. Because the sodium gave away 1 electron, it has a positive electric charge. The chloride that picked it up now had a negative electric charge. They have become ions with opposite charges, and will form an ionic bond. Its a bond they form because their opposite charges are attracting them and binding them together.

But they are still unreactive, Sodium and Chloride are very dangerous and toxic elements. But after their reaction theyve formed Sodium Chloride. Normal tablesalt, and completely harmless.

-Covalent Bonds.

A covalent bond happens when the atoms dont want to give away or snatch electrons as much. So the electrons sort of gets “half snatched”, and go between the two atoms. They are sharing the electrons. Water is like this. H²O. The oxygen is pulling a bit on thr electrons, but not enought to completely steal them.

This tells us that chemicams react to achieve noble gas structure.

Whats different to an electrical current then?

In metals, that can conduct currents, the electrons are essentially free to move around. So an electrical current are electrons moving from one point to another. This is why you have a positive end on a battery, and a negative one. Electrons move from the negative towards the positive end!

I will admit my knowledge on electricity is a bit lacking so i dont quite dare to respond more indepth on the electric part.

I apologize for any typos, i wrote this on mobile.

Electricity is electrons flowing through a wire. That’s fairly simple to understand.

What your nerve cells do isn’t simple and is really hard to ELI5.

Electrons have a negative charge. Ions like Na+ or K+ also have charge, but positive (metal stripped of one electron). They’re also bigger and tens of thousands of times heavier; an ion computer would be painfully slow.

You’re an ion computer.

Nerve cells are long, skinny, and often branched. They build up an electrical charge by pumping some of the positive ions out. When signaled by chemicals from the end (synapse) of the previous nerve, this opens a few floodgates (voltage-gated sodium channels) allowing positive ions back in. This flow opens nearby floodgates, creating a ripple of charge called an action potential that moves along the neuron’s length. When it reaches the end of the nerve, chemicals are released at the synapse to relay the ripple to the next nerve(s).

That is how your brain sends signals. Chemicals triggering a chain reaction of opening of ionic floodgates triggering chemicals. It’s slow (more than a million times slower than light) but also you can fit a lot of these things into a brain (far, far more than a computer chip has transistors) and they’re reasonably energy-efficient so it’s not all bad.