How Does Your Heart Know To Beat?

Do you ever wonder – why does my heart beat non-stop, all day, without me thinking about it?  You are not alone.  Your body is a complex mesh of parts intertwined with electric wiring, also known as your nervous system.  Your nervous system features your brain, spinal cord and nerves.  Together, they form the computer network that controls every aspect of your body.  Naturally, this means your nerves influence your heart.  Does this mean your nerves are the reason it knows to beat all day then?

What tells your heart to beat?heart

To answer this question, we need to review a little anatomy and physiology.  Your heart beats at a rate determined by its own electric system.  A node, known as the SA node, starts the electric reaction when an influx of calcium starts a chain of events.  The electric signal travels throughout the cardiac muscle causing them to contract and pump blood to your lungs and body.  It is similar to how Christmas lights work.  After you hang your lights around the house, you need to plug them in to an outlet for your decorations to turn on.  The electric impulse travels from your outlet to all of your light bulbs through the cord that connects them.  That is similar to what happens during a cardiac contraction!

How does the nervous system influence your heart?

Your heart beats at a rate determined by the SA node, a part of the cardiac electric system.  If this is so, why does it need outside help from your nervous system then?  The rate changes based on what you are doing.  Do you jog or go to the gym?  If you do, you may notice that your heart speeds up.  This is because your muscles need more blood and oxygen.  How does it know to speed up then?  Your brain monitors everything going on in your body, like a thermostat monitors the temperature in your house.  When it determines what is going on, it sends signals through your spinal cord and nerves to tell the heart to speed up.  Its function is incredibly important, and therefore under constant control by your central nervous system!

What would happen if there was an obstruction in your nervous system?

If there was an obstruction in the electric wiring to your heart, it would undoubtedly affect its function.  Certain conditions, like an arrhythmia, are an example of what may occur if the electric messages to your cardiac muscle are altered.  As a matter of fact, surgeons are now treating some forms of epilepsy by placing a pacemaker directly on the Vagus nerve – a nerve that is in direct contact with your heart.  One of the side effects of this procedure is that it may slow your heart rate!  This is because the electric messages to your heart are artificially altered by the pacemaker.

In summation, your heart beats all day because of the electric wiring in your body.  That is very fortunate for humans.  Can you imagine having to think about it pumping every time you needed it to work?  Thankfully, we have a system in place that does it all for us.  One that is often overlooked – your nervous system.