In those cases, the spread between the bid & ask goes to the market maker as compensation for making a market in a stock. For a liquid stock that is easy for the market maker to turn around and buy/sell to somebody else, the spread is small (narrow).
In cerebral hypoxia, sometimes only the oxygen supply is interrupted. Brain cells are extremely sensitive to a lack of oxygen. Some brain cells start dying less than 5 minutes after their oxygen supply disappears. As a result, brain hypoxia can rapidly cause severe brain damage or death.
Mild-to-moderate hypoxic brain damage may cause: 1  Headache. 2  Confusion. 3  Decreased concentration and attention span.  Mood swings and/or personality 1  change. Intermittent loss of consciousness. 2  Seizures. Poor coordination.