This question could be considered a follow-up question to Why is a lack of oxygen fatal to cells?, although the top answer there does not address why damage starts to pop in. The answer says this: ...
In animals temporary anaerobic respiration leads to the breakdown of the pyruvate formed by glycolysis into lactate. The buildup of lactate in the bloodstream is accompanied by a large number of ...
When a human being exhales $CO_2$, what is, by the numbers, the main source of carbon atoms exiting the body in this way? I mean what class of cells, or which tissues are the biggest on a pie chart of ...