ucsdhealthsciences:

Death of a cell

Apoptosis is the process of programmed cell death. Unlike necrosis, the premature death of cells, apoptosis is essential to life. For example, in embryogenesis, apoptosis occurs as the developing embryo pares away unneeded or unwanted cells and tissues. It’s part of the process that results in the separation and definition of the fingers. Apoptosis is one way the body fends off invasive cancers.

In the average human adult, an estimated 50 to 70 billion cells die each day due to apoptosis. In children, it’s about half that amount. When cells apoptose, they appear to collapse, forming misshapen bodies marked by blisters (called blebs) and sac (called vesicles). In the above image, by Thomas Deerinck and Mark Ellisman at the National Center for Microscopy and Imaging Research at UC San Diego, an apoptotic HeLa cell is surrounded by healthy counterparts.