Question

Biological death of the patient means death of tissues of the
A. Kidney
B. Heart
C. Lungs
D. Brain

Answer 1

Hint:- Biological death, as the entire organism dies, is a formal death of the body, but certain organs continue to operate for a while. After physical examination, doctors pronounce biological death as dead, such as no pulse, halting respiratory regulation, no shift of eyelids when concentrated light and the body loses its normal warmth.

Complete answer:
Death may include the organism as a whole (somatic death) or may be confined within the organism to cells and tissues. Injury, acute or chronic infection, and neoplasia (cancer) are causes of death in humans. Necrobiosis is called the physiological death of cells which are usually replaced during life; necrosis is called the death of cells triggered by environmental changes, such as an excessive loss of blood flow.
Somatic death is marked by the discontinuation of heart function and breathing and ultimately leads to the death of all body cells from lack of oxygen, although a person whose vital organs have not been destroyed may be revived for around six minutes after somatic death, a time referred to as clinical death. The advances of modern biomedical technology, however, have allowed the doctor to retain vital functions artificially for infinite times.
A series of irreversible changes that are of legal significance, especially in calculating the time of death, are accompanied by somatic death. This involve rigour mortis, livor mortis (discoloration of the body due to blood settling), algor mortis (cooling of the body), autolysis (breakdown of tissue after death by enzymes produced by that tissue) and putrefaction (invasion of the body by gastrointestinal tract organisms).
Brain death, which is now a legal condition for declared death in most jurisdictions, specifies that mental or involuntary motor processes above the neck, including pupillary reflexes to measure the jaw reflex, gag reflex, reaction to noxious stimuli, and any involuntary respiratory response, be absent for at least 12 hours. They can remain solely spinal reflexes. The monitoring time will be reduced to 6 hours if the patient has decided to be an organ donor.
From these discussions we can conclude that biological death of the patient means death of tissues of the brain. Therefore the correct answer is option (D).

Note:- The irreversible termination of all biochemical processes that maintain a living organism is death. Shortly after death, the remnants of a live organism tend to decompose. It is an unavoidable mechanism that inevitably happens in all living beings. A fundamental to human perception of the phenomena is the idea of death. The definition has many theoretical approaches and diverse meanings.
In describing death, one of the difficulties is to separate it from life. Death would seem to apply, as a point in time, to the instant at which life ceases. It is impossible to decide whether death has occurred, since the cessation of life processes is also not simultaneous across organ systems. Thus, such assessment involves the drawing of specific logical limits between life and death. This is confusing, and there is no agreement about how to describe life.