Fainting, syncope or blacking out is the momentary or short-term loss of consciousness followed by the come back to full restlessness. This loss of consciousness is come with loss of muscle tone that may be consequence with falling.
The human brain has numerous divisions, including two hemispheres, brain stem and the cerebellum. The brain needs blood circulation for supply of oxygen and glucose to its cells to continue life. For the body to be conscious, a part called as the reticular activating system situated in the brain stem wants to be turned on, and minimum one brain hemisphere wants to be functioning. For syncope/fainting to happen, either the reticular activating organism wants to lose its blood supply, or both hemispheres of the brain require being depressed of blood, oxygen, or glucose. For the brain to discontinue functioning, the circulation of blood must be temporarily disrupted to the entire brain or to the reticular activating structure.
Fainting is not at all caused because of head trauma, since collapse after a head injury is measured a concussion. But fainting cause head injury is normal, if anyone falls and injures him or herself.
Syncope/fainting is because of momentary reduction in blood circulation and therefore a lack of oxygen to the brain. This results to light-headedness, black out or unconsciousness. Temporary destruction of the blood circulation to the brain can be caused by heart situation and by circumstances that do not directly involve the heart.