In the thoracic cage, a wonder resides,
A muscular marvel where life gently abides.
A fist-sized organ, with chambers of four,
In rhythm it dances, a ceaseless encore.
With atria perched high, and ventricles deep,
It pumps the red rivers, awakening sleep.
The superior vena cava brings blood that is poor,
While pulmonary veins usher oxygen’s score.
Through valves like sentinels, ensuring the flow,
The mitral and tricuspid, disciplined and slow.
In diastole resting, then systole's might,
The heart sends its currents through arteries bright.
Oh, nodal ensemble—the SA node's call,
A spark of depolarization, igniting it all.
The atrioventricular node waits for the cue,
Then dispatches the signal like lightning anew.
Electrolytic symphony, ions in play,
Sodium and potassium lead rhythm’s ballet.
With each contraction, a wave does unfurl,
Through Purkinje fibers, like light through a swirl.
From aorta to capillaries, dance of exchange,
With tissues receiving what blood can arrange.
Glucose and oxygen, nutrients blend,
While carbon dioxide finds its way to the end.
Yet beyond mere mechanics, the heart knows to feel,
Its subject say love; its purpose is real.
With every heartbeat, emotions entwine,
As hormones cascade, in this vessel divine.
So marvel, dear soul, at this pulsing art,
The human experience wrapped up in the heart.
For though it beats steady, in silence it knows,
The science of life and the poetry flows.