List and describe the different categories of death.

Death has been broken down into the following categories:
 Functional death. The end of all vital functions, such as heartbeat and respiration.
 Cellular death. The gradual death of body cells after the heart stops beating. If placed in a tissue culture or, as is the case with various organs, transplanted to another body, some cells can remain alive indefinitely.
 Death. The moment the heart stops beating.
 Brain death. The end of all brain activity, indicated by an absence of electrical activity (confirmed by an electroencephalogram EEG) and a lack of reflexes. The notion of brain death is bound up with what we consider to be the actual person, or self. The destruction of a person's brain means that his or her personality no longer exists; the lower brain centers controlling respiration and circulation no longer function.
 Spiritual death. The moment the soul, as defined by many religions, leaves the body.