We’re used to thinking of the brain as an electric organ. The rest of the body? Not so much. But it would be a mistake to dismiss your other tissues as dumb hunks of electrically inert flesh. Even the protective layers of cells that compose your skin and line your organs use electrical signals to make decisions, according to recent research.

Results published in Nature show that cells use bioelectricity to coordinate a complex collective behavior called extrusion, a vital process that ejects sick or struggling individual cells from tissue to maintain health and keep growth in check. Merciless as it might seem, extrusion helps keep you alive. It’s vital for the health of protective epithelial tissues, and when it goes wrong, it can contribute to disease, including cancer and asthma. Until now, it’s been unclear how cells were singled out for this process.

According to the new results, as epithelial tissue grows, cells are packed more tightly together, which increases the electrical current flowing through each cell’s membrane. A weak, old, or energy-starved cell will struggle to compensate, triggering a response that sends water rushing out of the cell, shriveling it up and marking it for death. In this way, electricity acts like a health checkup for the tissue and guides the pruning process.