Final answer:
The brain can go without oxygenated blood for about five minutes before likely sustaining irreversible damage, and death is probable at around ten minutes without oxygen.
Step-by-step explanation:
The human brain can sustain itself without oxygenated blood for a very limited amount of time. Within approximately five minutes of oxygen deprivation, irreversible brain damage is likely to occur due to the brain cells' dependency on oxygen for ATP (adenosine triphosphate) production. By the ten-minute mark, if oxygen supply isn't restored, death is probable. However, in some exceptional cases such as cold-water drownings, the time frame can extend due to reduced metabolic rates, and successful resuscitation has been achieved even after longer periods without oxygen.