Welcome to The College of Heart Health – Heart Health 101
What muscle contracts 4300 times an hour; 104,000 times a day; over 37 million times a year and 3 billion times in a 78-year lifespan? The heart of course!
This is Dr. Jim for Be Healthy! Be Happy!
The heart is truly amazing on one hand, although quite simple on the other, which in many ways account for its extraordinary longevity.
Compared to other vital organs like the liver and the kidneys, the human heart consists of four pumps or chambers, a set of valves, a series of bundled electrical fibers and an array of blood vessels that harmoniously work together as the command center for the circulatory system.
The rhythmic beating of the heart balances the inflow and outflow of blood to and from the heart, which is essential to circulatory system function.
So, what keeps the heart rhythmically beating 3 billion times in a 78-year life span? A unique electrical system and very specialized heart muscle fibers is the answer.
As shown in the diagram, the SA node, the AV node and a series of bundled fibers call the Purkinje system, provide the electrical conduits for nerve impulses, which travel rhythmically through the heart, triggering the contraction and relaxation necessary for effective circulatory system action.
Even though the heart as an organ is mechanically simple, the composition of heart muscle fiber is specialized and complex. Due to its unique striated structure, heart muscle can contract, relax and contract continuously unlike skeletal muscle, which fatigues rapidly.
To pull all this off, heart muscle requires abundant sodium, potassium, calcium and magnesium, which is the subject of my next Heart Health 101 conversation.
In the meantime, Be Healthy! Be Happy! and power your path to happiness!
References:
Cleveland Clinic, 2003. Heart & Blood Vessels: How Does the Heart Beat? Online [Available at]: https://my.clevelandclinic.org/health/articles/heart-blood-vessels-heart-beat Accessed August 6, 2017.