Death is the irreversible cessation of all biological functions that sustain a living organism, marking the end of life. This includes the permanent stopping of the heart, breathing, and brain activity. Death is inevitable and occurs in all living organisms, with the body typically beginning to decompose shortly after death
. There are several ways to define and understand death:
- Biological death refers to when the cells and tissues of the body irreversibly stop functioning.
- Clinical death is when the heart stops beating and breathing ceases; this is often the moment when death is medically declared.
- Brain death is the irreversible loss of all brain functions, including the brainstem, and is considered legal death in many places.
- Psychic and social death describe loss of self-awareness or social recognition, respectively, but are more conceptual than medical
The definition of death has evolved with medical advances such as CPR and mechanical ventilation, which can temporarily restore heart and lung function even when brain function is lost, complicating the determination of death
. In summary, death is the permanent end of an organism's life processes, and while it is a biological event, it also has cultural, legal, and philosophical dimensions
