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.
Brain Damage Occurs Within Minutes From The Onset Of A Stroke, Study Reveals. FULL STORY. Scientists at the Brain Research Centre at the University of British Columbia and Vancouver Coastal Health Research Institute have found that harmful changes to the brain's synaptic connections occur within the first three minutes following a stroke.