Lee Swanson asks: How does the human body create electricity?
Fantastic question Lee. The shortest and most simple answer is- chemical reactions between different atoms and molecules within the body.
If all that seems a bit vague, let me give you the long answer that inherently needs to get a bit “sciency”. O’ how I love long sciency answers, much to the chagrin of certain readers who like to email me complaining about it. (I’m looking at you Bradley H.)
To start with, it’s necessary to explain a bit about what exactly electricity is. If you already know this, feel free to skip down a couple paragraphs. If not, read on!
What most people think of as electricity is simply the movement of an electrical charge, or potential. Sometimes known as a secondary energy source or an energy carrier, the electricity that powers everything from our television sets to our cars needs to be created from some energy source. When it comes to electricity, there are countless numbers of sources that can create electrical power. The most common energy sources for mass production are hydro-electric, nuclear, solar and wind. Technological advances have allowed us to harness these energies to give us wonders like dancing robots and smart-phone flashlights.
What are we harnessing from these energy sources? The power to move electrons. If you think back to junior high school science class, you might remember different atoms have different numbers of protons, electrons and neutrons. Protons being positive, electrons being negative and neutrons being neutral.
Each basic element, like the oxygen you breathe, and the sodium and potassium you eat, have a certain number of protons and electrons that will distinguish it from other elements. Most elements have the same number of electrons as they do protons. This will give it a balance between negative and positive charges. Protons reside in the nucleus (centre) of the atom while electrons rotate around the nucleus.
An interesting fact about electrons is, the energy they have is restricted to specific levels known as shells. These shells allow for specific spaces between the rotating electron and the centre protons- sort of like how planets orbit at different distances from the sun. Since negatively charged electrons are attracted to positively charged protons, the further away from the centre of the atom an electron is, the more loosely the electron is held to the nucleus and the easier it is to knock that electron free of it.
Electrons in the outermost shell of an atom, known as the valence shell, are so loosely bound to the nucleus, they can break away rather easily. If you get enough energy to break an electron free and cause it to move in a certain direction, the electron in the valence shell of the adjacent atom will flow to that atom because as we know, in most cases you need an equal electron to proton ratio in an element. These freely flowing electrons are what we’re harnessing from the outside power sources. This is what you are referring to as electricity.
When it comes to the electricity created in the human body, the energy source creating it is chemical. The energy created by chemicals has to do with the composition of the atoms and molecules present. All the elements we take into our bodies, like oxygen, sodium, potassium, calcium, magnesium etc. have a specific electrical charge- meaning they have a specific number of electrons and protons. Different chemicals are made up of different molecules. How those molecules are bound together, and how they react to other molecules near them is how chemicals create such energy.
When we take in our food, the large molecules within it are broken down in to smaller molecules and elements by our digestive system. Those smaller molecules and elements can be used by our cells to do work. That process is called cellular respiration. All of those molecules and elements have the potential to create electrical impulses, depending on the situations within the specific body systems at the time.
For a specific example of this sort of thing in action, one of the most commonly mentioned electrical currents created by the body is our heart rhythm. Our hearts contain a grouping of cells that reside in the upper right portion known as your Sinoatrial node or SA node for short. The cells within the SA node (pacemaker of the heart) contain electrolytes both inside and outside the cells. Some of the most common electrolytes within the body, as mentioned previously, are sodium, potassium, calcium, magnesium, phosphorus, and chloride. Sodium and calcium generally reside outside the SA nodes cells and potassium lies within.
These specialised cells allow much more sodium to enter the cell than allow for potassium to leave it. The result is a continually growing positive charge. Once that charge reaches a certain point, calcium channels open up in the cell membrane and allow for calcium to enter as well. This makes the interior of the cell extremely positive, known as an action potential. Once that potential reaches a certain point, it has enough “power” to discharge down the nerves of the heart. Ah the wonders of chemistry in action!
Electrolytes crossing cell membranes creating electrical discharges is only one of countless ways the body uses the food we eat to create energy and power to do work. But when you ask how the body creates electricity, the answer is as simple as “chemistry”. While this might not seem like the same electricity that powers the computer your using right now, at its core, it really is. The difference is what energy source caused the flow of electrons and how that flow created the reactions it did. So if your eyes didn’t glaze over during this little science tutorial, you now know the long answer to your question. If they did, you know the short answer as well. Either way, I hoped that helped.
If you liked this article, you might also enjoy:
- Fact or Myth: Sodium Raises Blood Pressure
- What Causes SIDS
- How Blood Works and the Difference Between Blood Types
- How Your Body Detects and Regulates Oxygen Level
- How the Heart Works
- Humans aren’t the only thing that harness chemical energy to create electricity. Batteries are another extremely common example of chemical energy being harnessed. You might think this type of harnessing is a new technological achievement that only modern man has been able to enjoy. The truth is, though, chemical batteries have been around since approximately 200 BC! The oldest known of this type were first discovered in 1938 by Wilhelm Konig just outside of Baghdad, Iraq. Consequently, they are known as “Baghdad batteries”. They were clay jars that contained a copper cylinder that encased an iron rod. Evidence of an acid was also found within the jars. While researchers and scientists continue to argue over there potential use and origins, what is known is that exact replicas have the power to create approximately .8-2 volts of electric current.
- We humans are very ingenious creatures and as such are creating new and exciting ways to harness the power within our bodies. One of the most interesting ways I have found lately is to create a flashlight powered by only our body heat. This year Ann Makosinski of Victoria, Canada invented a flashlight that is powered by simply holding it. The achievement earned her a spot as a finalist at the Google Science Fair. For those who think such feats are only for adults with copious amounts of life experience and education, Ann is only 15 years old! Seriously all the rest of you out there who are 15. Maybe a little less XBOX and a little more experimenting. Ann is making you all look bad.
- Since the electrical impulse created by our hearts is just that, electricity. The machine that doctors look at to determine how your heart is working (electrocardiogram or EKG) is simply a measure of that electrical current and it’s pathway. It was invented in 1903 by Dr. Willhelm Einthoven. Since this tool simply measures the electrical current within the heart, and not the actual squeeze of the heart itself, you could have a perfectly normal looking rhythm on the monitor and still be dead. This is known as PEA or pulseless electrical activity. If you see that flat line on the screen and the nurses begin to cry and the doctors begin to shake their heads in disappointment, it means there is no electrical activity in the heart, and you are most likely dead. If you’re curious how to read an EKG, it’s really not that hard and I’ve got you covered.
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