Senescence is a process in which cells reach permanent growth arrest without the death of cells as the whole cell division process comes to a halt.

It can either occur at the cellular level or senescence of the whole organism can take place.

It is characterized by a gradual functional decline eventuating heterogeneously across organ systems leading to a progressive deterioration ultimately leading to dysfunctioning of tissues.

This cellular program induces stable growth arrest.

The ageing process, on the whole, can be classified into three groups:

• Causes of age-associated damage – Primary

• Response to damage – Antagonist

• Consequences of Responses – Integrative

These cells pose a threat as they can cause cancers, damage tissues and degrade their functionality, increase chronic inflammation etc

Causes of Senescence may include Telomere Erosion, DNA Damage, Oncogene activation, irradiation, cell culture, stress on mitochondrial homeostasis. Excessive mitochondrial ROS has known to initiate cell ageing.