Apoptosis and Programmed Death

In fact, in a strict lexical sense, there is a big difference between programmed cell death (PCD) and apoptosis. The concept of programmed cell death was put forward in 1956. PCD is a functional concept, which describes that certain cell death in a multicellular organism is a predetermined part of individual development and is subject to strict program control. For example, when a tadpole changes into a frog, its tail disappears with a large number of cells dying during metamorphosis. Cell death must be involved in the disappearance of interdigital webs, jaw fusion, retinal development and normal development of the immune system of higher mammals. These various cell deaths in the process of body development have a common feature: scattered, one by one, they die and disappear from normal tissues, the body has no inflammatory reaction, and it is beneficial and necessary for the development of the whole body. Therefore, it is considered that programmed cell death in animal development is a developmental concept, while apoptosis is a morphological concept, describing a completely different form of cell death from necrosis with a complete set of morphological characteristics. However, it is generally believed that the concepts of apoptosis and programmed death can be used interchangeably and have the same meaning.