We are going to talk biology here.

The Neuron, or the nerve cell, as it is commonly called, is a type of cell that works by emitting electrical and chemical pulses to other cells, and well, mostly, other neurons, and those pulses function as a mens to tell other body parts what to do, as an example, muscle contraction happens because our muscle is connected to a type of nervous cell, that emits an electrical pulse, which in turn activates a protein chain, making the muscle contract and exerting force when we are lifting weights in the gym, for example. But how does that work? And why is it important? We will discuss that in a second, but first, lets learn a bit more about biology.

Biological structures are mostly composed of four main types of organic macromolecules: Polysaccharides, Proteins, Lipids and Nucleic Acids. Polysaccharides or polycarbohydrates are the main source of energy for our cells, and I mean not only electrical energy, but mainly chemical energy, we won't go into detail here, but the carbohydrates are used to regenerate ADP into ATP, which is the principal energy component of the cell. Nucleic acids are used in information storage, such as in the format of DNA and RNA, you may think of DNA as a hard drive, where information is stored for longer periods of time, while the RNA stores information in a more short term much like the RAM in computers.

The last two biopolymers, lipids and proteins, are what we are going to focus here, mostly because they compose a very important structure, that, while present in all living cells, is going to be important for our understanding of how the neurons communicate, electrically, and chemically. The name of that structure is The Plasma Membrane.

The plasma membrane, is a structure which its main function is to delimiter a cell perimeter, as it separates what composes the cell, from what is the intracellular medium. This separation occours mainly due to the hydrophobic nature of the membrane, which separates two highly aqueous, and very different mediums: the extracellular fluid and the cytoplasm. While the extracellular fluid hosts a plethora of biochemicals and other molecules, the cytoplasm is a much more controlled environment, as all the organelles are distributed in there, alongside a much different array of organic and non-organic molecules in comparison with the extracellular medium.

As noted, the plasma membrane serves the purpose of a great filter, preventing molecules from outside the cell from infiltrating the cytoplasm (and possibly causing havoc inside it), however there are a handful of different proteins that allows the flow of specific small molecules, and sometimes, atoms. These proteins are called transmembrane proteins.

Most transmembrane proteins function as an specific gate to a chemical, and just like a gate, it can be found at two different states, open and closed. If the gate is open, it will allow controlled flow of a chemical (most likely, an Ion, such as potassium and sodium) from one side to the other, while at the closed state, no ion can cross the membrane. This kind of transmembrane proteins allow controlled flow of these molecules from inside-out, and outside-in to the cytoplasm, and that is very very important, because it allows the cell to control the osmotic pressure between the different environments (intra and extracellular). This osmotic pressure difference also means that there is possibly a voltage difference between the same environments, caused by the difference of ions inside and outside the cell, and that control of the voltage difference is what enable the neurons to fire electrical pulses!

That oscillating pattern gives the neuron a voltaic charge, that pulses somewhat uniformly along the membrane, in a structure called the axon. That charge keeps going until it finds another neuron, and that neuron decides chemically, if it should or not excite its own membrane, creating another pulse, and that keeps going until an neuron acts as an insulator, preventing the charge from going forward. This pattern of activation/deactivation is what have inspired the artificial neuron networks of nowadays, but that's an story for another day.

Hope you enjoyed this story, and please stay tuned for others. See ya.