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.
Effects of Hypoxia. The organs most affected by hypoxia are the brain, the heart, and the liver. If the hypoxia is severe, irreversible damage can begin within four minutes of the onset. Coma, seizures, and death may occur in severe cases. Chronic, milder hypoxia can also cause damage to the major organs of the body.