Apoptosis - programmed cell death?

[Hi-fi]

In apoptosis is there a constant number devised by a scientist that states that a cell divides after (number) mitotic divisions?
If so whats the constant and who devised it?

[Cirbryn]

> "In apoptosis is there a constant number devised by a scientist that states that a cell divides after (number) mitotic divisions?"

You mean "states that a cell *dies* after (number) mitotic divisions"? Senescence can set in after a certain number of divisions due to loss of telomeres after each division. This is different from apoptosis, however, which is a cell's self-destruct mechanism and is triggered by specific circumstances unrelated to number of divisions.

The number of divisions a line of cells can undergo before undergoing senescence (assuming the telomeres aren't repaired by the enzyme telomerase) is about 85.

[Peter]

I am not aware of any such constant Apoptosis is not that simple and is controlled by various factors .
For instance during the development of the foetus in the mother, the differentiation of fingers and toes occurs because cells between the fingers apoptose with the end result that the digits are separate.

The type of apoptosis you are referring to in your question is known as replicative senescence and is thought to be controlled by telomere length.

Have a look at the links below, I hope they are of some help to you.

[tracyzh130]

Apoptosis is the process of programmed cell death. Apoptosis occurs during normal cell turnover, development and in the immune system. Excessive apoptosis will cause atrophy, such as in neurodegenerative diseases, but too little apoptosis results in uncontrolled cell proliferation in cancer. Apoptosis is highly related with caspases, Bcl-2 proteins and granzyme B.