Cori Cycle: The Lactate Shuttle Between Muscle and Liver

This 2D simulator diagrams the Cori cycle — the continuous relay of lactate from an exercising muscle to the liver, where gluconeogenesis rebuilds it into glucose that flows back to fuel the muscle again. Exercise intensity drives anaerobic glycolytic lactate output, liver capacity sets how quickly hepatic gluconeogenesis can clear that lactate under Michaelis–Menten saturation kinetics, and a blood-flow slider controls how fast packets physically transit the vessel between the two organs. Drag the diagram to pan and scroll to zoom into the flow, watch the live history strip track blood lactate, glucose output and net ATP balance over time, and read the kinetics panel to see exactly where the current lactate level sits on the saturating clearance curve. The net systemic ATP balance is always negative, since the liver spends three times more ATP rebuilding glucose than the muscle earned by making lactate in the first place.