Final answer:
Permanent brain damage can occur within 5 minutes without oxygen, as neurons require constant oxygen to produce ATP and are highly sensitive to oxygen deprivation.
Step-by-step explanation:
The lack of oxygen in the brain for as little as 1 to 2 minutes starts to deteriorate brain cells, and permanent brain damage is likely to occur within 5 minutes of oxygen deprivation. This serious condition can lead to a stroke or cerebrovascular accident (CVA), where brain cells die due to the lack of oxygen.
It is crucial to understand that neurons have a very high requirement for a constant supply of oxygen for the production of ATP, and they are sensitive to even brief periods without oxygen. Consequently, rescue efforts, including the administration of oxygen or CPR, should be initiated as soon as possible to prevent long-term neurological damage or even death.