From one cell to you

Your body has about 37 trillion cells, of around 200 different kinds. They aren't just piled together. They're organized like a company, from single workers up to whole departments. Zoom in and see the levels for yourself.

Grade 8 science · CellsCells, tissues, organs, systemsAbout 10 min

Part 1 of 4 · Zoom in

Five levels, one dinner

Where does your dinner go? Start with the whole body and zoom in, one level at a time.

Try: tap the glowing part to zoom in.

Part 2 of 4 · An organ is a team of tissues

Build a stomach wall

Lots of people think an organ is made of one kind of cell. Your stomach needs at least four different tissues, each one a sheet of similar cells doing one job. Build the wall, then test your stomach on a sandwich.

Try: tap a tissue, then tap the layer it goes in. Test any time, even half-built.

The wall, from inside to outside

Tissues

Part 3 of 4 · Which level?

Cell, tissue, organ or system?

Quick test: one kind of cell? A sheet of similar cells? Several tissues working as one structure? Several organs on one big job?

Try: tap a thing, then tap its level.

Part 4 of 4 · When one level breaks

A problem climbs the ladder

Because every level is built from the one below, damage at the bottom doesn't stay there.

Putting it back together

The ladder, top to bottom

SystemSeveral organs on one big job: the digestive system breaks food down and takes it in.
OrganSeveral tissues built into one structure: the stomach, a leaf.
TissueA sheet or bundle of similar cells doing one job: smooth muscle, the palisade layer.
CellThe smallest living unit, specialized for its job.

Every one of those cells came from another cell, and each one gave up doing everything so it could do one job well. That's the whole Cells unit in one picture.