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Scientists estimate that there are more than 30 trillion cells in the human body.

That is more than 30 trillion microscopic sacks of cytoplasm and proteins all collaborating

together to do the really complicated things necessary to keep us alive.

Which raises a big question.

How do these tiny cells, none of which have their own brains?

How do they all work together?

I'm a cell biologist who looks at how cells communicate with one another, how they talk

to each other, and they talk through molecules going from one cell to the adjacent cell.

Dr. Sandra Murray is a professor of cell biology and physiology at the University of Pittsburgh,

and she's been a lifetime trying to understand the language of cells.

These could communicate with things like the blood vessels, bring information to the cells,

and the cells on the outside get a molecule that says, let's do something.

They get a hormone carried in the blood, and that blood gets only to the outside.

And those cells say, oh wow, there's something happening.

I have to move, let's move, let's move.

Then the molecule is moving from cell to cell to cell to cell, and then all of a sudden

all the cells becoming a team.

And so there's an example where you would use a hormonal stimulation and get the entire

population doing something together.

Like say, deliver a baby.

The smooth muscles of the uterus where the baby is developing, those cells need to do something

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