Why is it important for muscle cells to export lactate into the bloodstream during heavy exercise?

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K. Our next question is a true or false question with two statements that we have to determine whether they are true or false. So statement one says it is important for muscle cells to export lactate into the bloodstream during heavy exercise to prevent the accumulation of lactate in the muscles. And the number two says the kidneys convert lactate back into glucose which helps sustain energy production. So let's start with statement one thinking about heavy exercise. So what happens during heavy exercise? The answer is the muscles get depleted of oxygen. So now that the muscles have had their oxygen depleted, the cells can't perform cellular respiration to get their source of A TP, which they need to continue to function in this heavy exercise situation. So we have this alternative pathway where so instead of being oxidized all the way to carbon dioxide through cellular respiration, glucose gets converted into pyruvate, but goes through that first step of glycolysis. So our overall reaction is that glucose is converted to lactate. And in that process N AD plus is produced and this allows glycolysis to continue. Since glycolysis requires a supply of N A DPP N AD plus, excuse me. So without this process of fermentation, glycolysis would come to a halt without the energy plus that it needs to continue. So we know what becomes of and then you've got this source of N AD plus that can allow glycolysis to continue since it provides that region that is necessary. Now, what would be the issue with the accumulation of lactate? So you can see where if all of your glucose is being converted to lactate, you're going to have a lot of lactate sitting around. Well, lactate or lactic acid will reduce the ph of their environment and this reduced ph affects the enzymes and proteins in those cells. They don't work as well. So you don't want all of this acidic lactate building up and having this effect. This includes the enzymes involved in glycolysis. And of course, if our glycolysis enzymes are inhibited, then the small amount of A TP that's being produced by glycolysis is not being produced as much as it should be. So you can see where that would be a problem. So this is all a long way around to say that statement. One here is true that it's important for the muscle cells to export lactase. Now, our second statement is the kidneys convert lactate back into glucose, which helps sustain energy production and we don't need to even go into a longer explanation. The problem is right at the beginning, it is the liver that converts lactate back into glucose helping to sustain energy production. So statement two is false. So again, we had to evaluate the true false nature of these two statements here. And statement one was a true statement and a statement too is false in the next video.

Why is it important for muscle cells to export lactate into the bloodstream during heavy exercise?

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Key Concepts

Lactate Production

Lactate Clearance

Energy Metabolism