How the heart actually pumps blood - Edmond Hui

For most of history,

humans had no idea what purpose the heart served.

In fact, the organ so confused Leonardo da Vinci,

that he gave up studying it.

Although everyone could feel their own heart beating,

it wasn't always clear what each thump was achieving.

Now we know that the heart pumps blood.

But that fact wasn't always obvious,

because if a heart was exposed or taken out,

the body would perish quickly.

It's also impossible to see through the blood vessels,

and even if that were possible,

the blood itself is opaque,

making it difficult to see the heart valves working.

Even in the 21st century,

only a few people in surgery teams

have actually seen a working heart.

Internet searches for heart function,

point to crude models, diagrams

or animations that don't really show how it works.

It's as if there has been a centuries old conspiracy

amongst teachers and students

to accept that heart function cannot be demonstrated.

Meaning that the next best thing

is simply to cut it open and label the parts.

That way students might not fully grasp the way it works,

but can superficially understand it,

learning such concepts as

the heart is a four-chambered organ,

or potentially misleading statements like,

mammals have a dual-circulation:

one with blood going to the lungs and back,

and another to the body and back.

In reality, mammals have a figure-eight circulation.

Blood goes from one heart pump to the lungs,

back to the second heart pump, which sends it to the body,

and then back to the first pump.

That's an important difference

because it marks two completely different morphologies.