An Ode To Blood

I don't remember really when,
For I was extremely young then,
I checked the cells I had to cart,
In all my travels from the heart.

My constant journey has been planned,
There is no special place to end;
No single venue may I miss,
For many outlets I must please.

Not a single stop can I make,
And cleansing foods I must partake,
Sometimes I have a friend with me,
From outside he comes in daily.

Oxygen is his chosen name,
The trips we make are not a game,
For at times, on our winding way,
Meet enemies who want to stay.

They stick to many a roadside,
Hoping from me to get a ride,
But they are elements real bad,
And make my host extremely sad.

They call their sticky selves Platelets,
They are very friendly with Fats,
Together Heart they will attack
Whom I am supposed to protect.

So my travels will never end,
For Heart who is my host and friend,
His arteries I have to flood,
So now you know, my name is Blood.