What is the first thing that happens when a salamander loses a limb?

Skin cells surge across the wound's surface.

What is the wound epidermis, and what is its function in tissue repair?

The wound epidermis is a new layer of skin that forms over the injury. It signals cells in the limb stump to dedifferentiate.

Dedifferentiation is when cells revert from fully developed limb tissues back into earlier, less specialized progenitor cells.

Stem cells reactivate, multiply, and contribute to the formation of the blastema.

A blastema is a structure made of recycled progenitor cells that forms at the injury site. It is responsible for growing the new limb.

Grade 7th Grade · Science · 40 min

I can describe and explain the process of tissue repair after an injury.

TED-Ed · 5:28

How do animals regrow their limbs? And why can't humans do it? - Jessica Whited

3 key concepts

1
When salamanders lose a limb, skin cells quickly move across the wound to form a new layer called the wound epidermis.
2
The process of dedifferentiation reverts cells from fully developed limb tissues back into earlier, less specialized progenitor cells.
3
The blastema, made of recycled cells, is a structure that grows new cells and organizes them into muscle, bone, skin, and nerve tissue to form a functional limb.

7 questions · Multiple choice & Short answer

Quick comprehension check

“Describe the steps of tissue repair in salamanders after losing a limb, including the role of the wound epidermis and the blastema.”

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