Reversible state of reduced sensory and motor action with environment. Brain mimics activity as if you are awake. Can remember about 7 items for couple seconds. Unless try to save it, will lose it. 4-8 mins of o2 deprivation, brain damage or death. Changes in blood-brain barrier: protects brain from harmful chemicals. Can be also due to inflammation, swelling (3 days after stroke) Control high bp, smoking, high cholesterol, physical inactivity. Interruption of blood flow due to blood clot. Loss of cells in brain area which regulates dopamine levels. Can be from tremors, or freezing of movement. Memory loss occurs with it; memory loss alone does not mean you have it. Decline of # brain cells, causes shrinking brain tissue and deteriorating mental ability. Combo of memory loss, confusion, general intellectual decline. Early stages: anxious and depressed because aware of the loss. Later stages: more dependent, need full- time care.