Q: Given a passage and a query based on the passage, generate an unambiguous, concise and simple answer to the query from information in the passage. Note that the answer may not be present in exact form.
In terms of energy allocation, our brains require 25% of the body's total stored energy (which is a lot if you think about it), with the rest going to fuel our muscle tissues and red blood cells. We can go for about six hours in this glucose-burning mode, which is why we tend to get a bit cranky if we have to go without food for longer than that. The point is that not all of your cells die quickly without oxygen. In surgeries they cut off blood supplies for up to hours and tissues don't die. Your brain is really what needs the oxygen. It has a huge metabolic requirement, and it needs a constant supply of oxygen for cellular respiration. In essence, your body is buying you some valuable time to give you a fair chance of finding some food. 0-6 hours after eating. Soon after eating, our bodies start to break down glycogen (molecules that store energy) to produce glucose (an important carbohydrate that fuels cells). []Helassaid 93 points94 points95 points 5 years ago (16 children) Most cells in the body can respire anaerobically and do a decent job of surviving the ensuing onslaught of organic acid byproducts... except brain cells, which are wholly dependent on oxygen because of their high rate of metabolism. It depends on the tissue type and on the circumstances. Brain cells start to die after 5 minutes, while heart cells die after 2 hours without oxygen. You can slow down the process by cooling down the body. inf3rno Oct 27 '15 at 2:50 1 So, in summary: although I could find no solid evidence on how long a limb can live without its blood supply, it appears to be about 2-4 hours (some sources say 5-8); however, I would like to add that your case appears to be a severe case of an asleep limb, you were/are likely in no danger. When a limb falls asleep, it is getting the nerve pinched off for a time as well as loosing some blood flow. However, this is not a complete loss and so your arm is able to survive because it is still receiving enough oxygen and other nutrients to sustain its existence (as well as having toxins and CO2 pumped away from it). The human body can go without oxygen for about five to ten minutes, and about three to eight days without water. But remarkably, people have been known to live upwards of 70 days without food. How is this possible? The crucian carp can live in anoxic water for months at temperatures close to freezing. Similarly the turtle, Trachemys scripta, can withstand anoxia for 48 h at 20 C and at least 3 months at 3 C. Most of the book is in fact devoted to a detailed look at the adaptions that allow these species to survive without oxygen for a long time. I've heard it said various times that the body's tissues will begin to necrotize after being cut off from the blood supply for only a few minutes, but that can't be true. Query: how long can a body cell live without oxygen
A:
Brain cells start to die after 5 minutes, while heart cells die after 2 hours without oxygen.