Thanatology deals with death in all its aspects. There is a progression from clinical death to brain death, biological death and then cellular death. Brain death follows immediately clinical death due to lack of oxygen. First the cerebral cortex, then cerebellum and then lower brain centers die. Ultimately the brain stem and the vital centers die. Thereafter the process of cellular death begins.
In the study of Thanatology, Death is of two types (1) somatic, systemic or clinical, and (2) molecular or cellular.
THE MOMENT OF DEATH
Death is not an event, it is a process. Historically (medically and legally), the concept of death was that of heart and respiration death, i.e. stoppage of spontaneous heart and breathing functions. Heart-lung bypass machines, mechanical respirators, and other devices, however have changed this medically in favor of a new concept ‘brain death’, that is, irreversible loss of cerebral function.
Brain death is of three types:
(1) CORTICAL OR CEREBRAL DEATH with an intact brain stem. This produces a vegetative state in which respiration continues, but there is total loss of power of perception by the senses. This state of deep coma can be produced by cerebral hypoxia, toxic conditions or widespread brain injury.
(2) BRAIN STEM DEATH.
It is well recognized that brain-stem death is compatible with aspects of “brain life”. For example, neurological regulation of hormonal secretion, an electroencephalographic activity possibly representing cortical function, commonly exist even when the formal criteria for diagnosing brain death are satisfied.
(3) WHOLE BRAIN DEATH, i.e. permanent cessation of functions of cerebrum, cerebellum and brain stem.
Thanatology helps in analyzing all the factors related to death and its causes.
