Here's my story,
I’ll tell you my story,
After I breathe some O-2,
Then exhale the air, 
As I go and prepare,
This story I’m telling to you...
To breathe it’s a breeze,
We all need to breathe, 
Animals, insects,
Fish in the seas! 
Air through our mouth, 
Or in through our nose,
Down through our trachea,
That’s how it goes!
Through bronchial tubes,
Into the lungs,
For body to use,
Like ladders use rungs...
Alveoli come next,
Cool little sac,
Like ravioli and cheese,
They deliver a snack!
Oxygen to blood,
They’re really quite nice,
Remove C-O-2,
They’re all working twice...
When we exhale,
It let's humans speak,
Move vocal cords,
To sing or to squeak...
Respiration is cool,
It’s not very shoddy,
It’s a really great system,
Found in our body...
Cardiovascular system,
Consists of veins and arteries,
For blood flow, 
You can't miss ‘em…
Surely, I am circulatory,
Pumping round and round,
Beating heart and blood vessels,
I surely will astound…
Brought by 'blue' veins,
To the heart,
To lungs is where blood's pumped...
Oxygenated by those lungs,
This system can't be trumped!
Blood from lungs,
Returns to heart, 
And then to artery,
Which carry blood to every organ,
In every part-a-me!
Surely, I am circulatory,
Pumping round and round,
With my heart,
And blood vessels,
I surely will astound!