How does your body heal a cut?

A blade slices through skin and nicks a tiny blood vessel. The vessel squeezes, platelets stick and grow spiky arms, and fibrin threads knit a net that traps red cells into a clot. Outside it dries into a scab while new skin grows back underneath.

Transcript

Under your skin, blood is always flowing. Ouch! A sharp blade slices in. The wall breaks and blood leaks out. The vessel squeezes to slow the blood.

Here comes a tiny platelet. It bumps the broken wall and sticks! Now it grows spiky arms. And calls more platelets over.

More platelets stick and pile up. They plug the hole! Sticky fibrin threads grow over the plug. It traps red cells. That is a clot!

The leak is sealed! Outside, the clot dries into a scab. Underneath, new skin grows back. Squeeze, stick, net, scab, heal!

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