Understanding Heart Function and Circulation

Study Notes

For most of history, humans were unaware of the heart's purpose, with even Leonardo da Vinci giving up on studying it.
The heart's function was not obvious because it stops working when exposed or removed, and the blood vessels and blood itself are opaque, making it difficult to observe the heart valves.
Even in modern times, only a few people in surgery teams have seen a working heart, and online resources often provide crude models or diagrams that don't accurately demonstrate heart function.
The traditional approach to teaching heart function is to cut it open and label the parts, which can lead to superficial understanding and misconceptions, such as the idea that mammals have a dual-circulation system.
In reality, mammals have a figure-eight circulation, where blood flows from one heart pump to the lungs, back to the second pump, and then to the body and back.
Medical professionals are the only ones who fully understand how the heart works, as they get to observe the motion of the heart's valves.
To demonstrate heart function, a fresh heart (such as from a sheep or pig) can be immersed in water and modified by removing the atria and trimming them down to the tops of the ventricles.
By running water into the ventricle from a tap, the ventricular valve can be seen opening and closing, mimicking the flow of blood in life, and the efficiency of the valves can be observed.
The heart's valves are capable of closing against each other with minimal wear and tear, allowing them to function seamlessly for over 2 billion beats in a lifetime.

Description

Discover the intricacies of the heart's purpose and function, and how it was misunderstood for centuries. Learn about the figure-eight circulation system in mammals and how medical professionals can observe the heart's valves in action. Explore a unique method to demonstrate heart function using a fresh heart and water.