A hairy death
Apoptosis or programmed cell death is an essential part of life. For example, it’s critical to human development. Where would we be if every fetal cell survived? Some cells must die to form, say, our fingers and toes; others must perish to shape our functional brains.
Cells frequently commit suicide for the good of the whole. They may become apoptotic in response to viruses or gene mutations in order to prevent further damage. Menstruation relies upon programmed cell death.
Apoptosis may be necessary, but it’s not necessarily pretty. Above is a scanning electron micrograph of several cultured HeLa cancer cells. The cell at the center is undergoing apoptosis. During the process, the cell’s cytoskeleton breaks up, causing the outer membrane to bulge and decouple. The resulting wart-like structures are called blebs, which eventually break off and are consumed by phagocytic cells for recycling.
The hairy extensions are filopodia, extremely tiny extensions of cytoplasm used by cells for sensing, migration and cell-cell interactions.