How Does the Human Body Generate and Utilize Electrical Energy?

Without electrical energy, this article would be unreadable, not due to a malfunctioning computer, but because your brain would cease to function.

Every action we perform is governed and powered by electrical impulses traveling through our bodies. As foundational physics teaches us, all matter consists of atoms, which are composed of protons, neutrons, and electrons.

Protons possess a positive charge, neutrons remain neutral, and electrons carry a negative charge. Interestingly, atoms can acquire either a positive or negative charge by gaining or losing electrons. The movement of electrons between atoms is what constitutes electricity. Given that our bodies are composed of vast numbers of atoms, we are capable of generating electrical energy.

When discussing the nervous system transmitting "signals" to the brain, synapses "activating," or the brain instructing our hands to grip a door handle, we are essentially describing electricity facilitating communication between two points.

This process resembles a digital cable signal transmitting binary code to deliver episodes of "Law & Order." However, in our bodies, electrons don't travel through wires; instead, an electrical charge leaps from one cell to another until it arrives at its target.

Almost every cell in our body has the capacity to produce electricity. In this article, we will explore the significance of electricity in the human body and uncover how it is generated.

The foundation is straightforward: At this moment, any cells in your body not actively transmitting signals maintain a slight negative charge. The real intrigue begins from there.

A Charged Discussion

A negative charge is the default resting state of your cells, resulting from a minor imbalance between charged atoms inside and outside the cells.

These atoms are referred to as ions, and the aforementioned imbalance lays the foundation for your body's electrical potential.

Many of the ions in question (though not all) are either sodium or potassium atoms. These two elements are crucial and will play a significant role in our discussion.

Both potassium and sodium ions are positively charged. When a cell is inactive, sodium ions are more concentrated outside the cell, while potassium ions are more abundant inside the cell than outside.

In general, the area outside the cell will have a more positive charge compared to the space inside the cell, making the interior relatively negative.

This condition is referred to by scientists as the cell’s resting membrane potential, or RMP.

Additionally, the charge difference across the cell membrane creates an electrochemical gradient between the cell’s interior and its immediate external environment.

Channel Guide

When a cell is in the RMP stage, both sodium and potassium ions are present on either side of the membrane. Interesting, right?

But how do these ions cross the membrane? How do they move in and out of the cell? This is where ion channels play a role. These are specialized pathways in the membrane that allow specific ions to pass through. (Fun fact: In most cells, potassium channels are more abundant than sodium channels.)

Let’s take a moment to understand their function. According to Harvard Extension School’s official YouTube channel, the “difference in total charge between the inside and outside of the cell is known as the membrane potential.” (This is where the term “resting membrane potential originates. Makes sense, doesn’t it?)

When the membrane potential of a cell changes—meaning the internal charge shifts relative to the external charge—it can trigger the activation of specific ion channels embedded in the membrane.

Many channels only permit ion transfer when the cell’s membrane potential changes by a specific threshold. These pathways are formally known as voltage-gated ion channels.

Each voltage-gated ion channel is selective, allowing only a specific type of ion to move in or out of the cell.

Your neurons, specialized cells in the nervous system that transmit information throughout the body, feature both sodium and potassium voltage-gated ion channels in their membranes. Got it?

These channels can change a neuron’s membrane potential by allowing specific ions to enter from the outside. If sufficient ions pass through, the cell will no longer maintain its RMP.

Human Voltage

Alright, the previous sections have set the stage. Now, there’s another key term we need to explore before moving forward: action potential.

“An action potential is a swift series of changes in the voltage across a membrane,” states the U.S. National Library of Medicine. Essentially, an action potential is a two-phase electrical wave: depolarization followed by repolarization.

Imagine accidentally touching a hot stove—it can happen to anyone.

Action potentials enable neurons to communicate with each other. In this scenario, the neurons in your hand must relay an urgent message to your brain about the scorching stovetop.

Recall that at RMP, sodium ions are more concentrated outside the cell. However, the stimulus from the hot stove example triggers the opening of sodium voltage-gated ion channels in the nearest neuron’s membrane. This allows a flood of sodium ions to rush into the cell.

This, my friends, is the “depolarization” phase—a complete game-changer. The sudden influx of sodium ions makes the cell’s interior more positively charged than its surroundings, flipping the RMP scenario on its head.

The surge of sodium ions increases the internal voltage, but this is just the first phase. Next, the neuron enters “repolarization.” With sodium-potassium pumps expelling sodium ions and drawing in potassium ions, the cell membrane restores RMP, making the neuron’s interior negatively charged once more.

Depolarization and repolarization form the dynamic duo behind action potentials. These electrical waves can trigger a domino effect among neurons, sending signals to your brain for interpretation and action.

A Well-tuned Network

And there you have it—the key to the electrical signals that command your heart muscles to beat and inform your brain, via your eyes, that it just processed the word “brain.” You know, critical functions like that.

Unsurprisingly, any disruption in your body’s electrical system can lead to serious issues.

An electric shock can interfere with the system’s normal functioning, akin to a power surge. A lightning-level shock can halt your body entirely, frying the electrical processes. But that’s a tale for another day.