Brain death involves the cessation of which system's function?

Brain death is defined as the irreversible loss of all functions of the brain, including the brainstem, which plays a crucial role in regulating basic life functions. When brain death occurs, there is a complete and permanent cessation of all neurological activity. This includes not only higher brain functions associated with cognition and consciousness but also vital functions controlled by the brainstem, such as respiration and certain reflexes.

Since the nervous system is responsible for coordinating all bodily functions and maintaining consciousness, the determination of brain death hinges primarily on assessing the functionality of this system. While the other systems mentioned—circulatory, respiratory, and endocrine—are affected by brain death, they are not the primary focus when defining the condition itself; rather, they are consequences of the loss of nervous system function. Therefore, focusing on the cessation of nervous system function accurately captures the essence of brain death.