Answer to Question 1
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 electroencephalogra m 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.
Answer to Question 2
Health-care proxies and living wills are the two most common advance directives.
A health-care proxy is an advance directive that gives someone else the power to make health decisions on your behalf. This advance directive is also called medical power of attorney or health-care power of attorney. People typically name a relative or close friend as their agent.
A living will (also called health-care directive or physician's directive) is an advance directive that allows an individual to indicate whether he or she wants or doesn't want all possible medical treatments and technology used to prolong their lives. Living wills are most effective when they focus on priorities and goals rather than on how to achieve them.