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.
Symptoms of mild brain damage from a lack of oxygen, or cerebral hypoxia, include short attention span, poor coordination and faulty judgment, according to MedlinePlus. Signs of more serious cerebral hypoxia are coma, inadequate pupil response to light and suspension of breathing. Full Answer >.