According to the Buddhist theory of mind (in Abhidharma or Buddhist Psychological terms), there are eight factors that together comprise a human being. The first four are collectively known as body -- although most frequently referred to in the aggregate as form (rupa). These are the Four Great Elements or mahabhuta (dhatu).
- Earth (the quality of hardness)
- Fire (heat)
- Water (cohesion)
- Wind (motion)
- Feeling (sensation)
- Perception (six sense-organ and object contact)
- Mental formations (e.g., will or volition, etc.)
- Consciousness (reflective awareness)
Brain vs. Mind
The Buddha depicted among angelic devas in the Fine Material world.
One might even go so far as to argue that the brain cannot operate, and therefore normal human consciousness (or the epiphenomenal mind) cannot function, in the absence of blood -- that is, without nutriment (glucose) and oxygen. Glucose is not considered the brain, and neither are the lungs. Yet without them, there is no brain function. This is only to say that it is an artificial distinction being drawn:
Eidetic representation of Dependent Origination's complexity (vimokkha)
Since that was the Buddha's goal -- nirvana or "the end of suffering" -- rather than psychology or physics for their own sake, no ultimate ontological resolution is to be found in the Dharma. However, enlightenment is possible. And with enlightenment, the pursuit of all these questions is possible. One may see and know for oneself and come to understand that such questions are not the ultimate and do not pertain to full liberation from ignorance and the end of suffering. If they did, the Buddha explained, he would have taught them. Instead, from all that he knew, he limited himself to teaching only two thing, suffering (dukkha) and the end of suffering (nirvana).