Definition - the state of full awareness of the self and one's relationship to the environment.
Clinically - determined at the bedside by the responses of the pts to the examiner; it is possible for a pts to be conscious yet not responsive (e.g. paralyzed) or psychological reasons (decides not to response);
Consciousness components:
Content = sum of all functions mediated at a cortical level (cognitive) and affective responses;
Arousal - cognition is not possible without a reasonable degree of arousal.
Impairment of cognitive functions or arousal = impaired consciousness.