How the human body uses electricity

Electricity is everywhere, even in the human body. Our cells are specialized to conduct electrical currents. Electricity is required for the nervous system to send signals throughout the body and to the brain, making it possible for us to move, think and feel.

So, how do cells control electrical currents?

The elements in our bodies, like sodium, potassium, calcium, and magnesium, have a specific electrical charge. Almost all of our cells can use these charged elements, called ions, to generate electricity.

The contents of the cell are protected from the outside environment by a cell membrane. This cell membrane is made up of lipids that create a barrier that only certain substances can cross to reach the cell interior. Not only does the cell membrane function as a barrier to molecules, it also acts as a way for the cell to generate electrical currents. Resting cells are negatively charged on the inside, while the outside environment is more positively charged. This is due to a slight imbalance between positive and negative ions inside and outside the cell. Cells can achieve this charge separation by allowing charged ions to flow in and out through the membrane. The flow of charges across the cell membrane is what generates electrical currents.

Cells control the flow of specific charged elements across the membrane with proteins that sit on the cell surface and create an opening for certain ions to pass through. These proteins are called ion channels. When a cell is stimulated, it allows positive charges to enter the cell through open ion channels. The inside of the cell then becomes more positively charged, which triggers further electrical currents that can turn into electrical pulses, called action potentials. Our bodies use certain patterns of action potentials to initiate the correct movements, thoughts and behaviors.

A disruption in electrical currents can lead to illness. For example, in order for the heart to pump, cells must generate electrical currents that allow the heart muscle to contract at the right time. Doctors can even observe these electrical pulses in the heart using a machine, called an electrocardiogram or ECG. Irregular electrical currents can prevent heart muscles from contracting correctly, leading to a heart attack. This is just one example showing the important role of electricity in health and disease.

References CrashCourse. “The Nervous System, Part 2 - Action! Potential! Crash Course A&P #9.” YouTube video, 11:43. March 2, 2015. https://www.youtube.com/watch?v=OZG8M_ldA1M. Essentials of Anatomy & Physiology. “Voltage-Gated Channels and the Action Potential.” The McGraw-Hill Co., Video. 2016. http://highered.mheducation.com/sites/0072943696/student_view0/chapter8/animation__voltage-gated_channels_and_the_action_potential__quiz_1_.html. Nelson, David L, and Michael M Cox. 2013. Lehninger Principles of Biochemistry 6th Ed. Book. 6th ed. New York: W.H. Freeman and Co. doi:10.1016/j.jse.2011.03.016.