The Controller and Acid-Base Physiology: An Introduction to a Complex Process
Compensatory Mechanisms
Use Animated Figure 7-6 to select a primary acid-base disturbance and play the primary disorder animation to observe the effect on the pH caused by the change in PCO2 or bicarbonate. Then play the secondary (compensatory) process and note how it serves to move the pH back toward normal.
The goal of these compensatory mechanisms is to restore the pH of the blood to normal or near-normal levels. However, the compensation never results in a pH that is all the way back to 7.40, with the exception of the metabolic compensation for a chronic respiratory alkalosis. If the pH is fully restored to 7.40 or beyond, you should look for the presence of two, simultaneous, primary acid-base disturbances (more on how to recognize this in the next section).
Respiratory compensation for metabolic acid-base disorders can occur within seconds to minutes. The sensitivity of the chemoreceptors and the timely response of the controller to changes in their output ensure this. Metabolic compensation for respiratory disorders, however, generally requires 2 to 5 days to be fully evident. The kidneys’ ability to adjust levels of hydrogen ion and bicarbonate is not as rapid as the respiratory response.
Using this figure with an AI assistant
If you use an AI assistant that can see this page, whether it is built into your browser or opens the page in its own browser, you can ask it about this figure, ask it to play a disorder and its compensation and explain what you see, or ask it to take you through one of the tours. It can choose the disorder, play the figure forward or back, and point out parts of the balance. The rest of this section is for the assistant.
An AI assistant can change this figure in two ways. In a browser with WebMCP, the page offers its actions as tools. In the page's scripts, the same actions are in window.physiologyFigures, with a description of the controls and what they mean, the parts it can point out, the values shown, the model's limits, and the Show Me tours. Both play the figure the way the buttons do, wait for it to show the change, and return the exact values. The page address always holds a link to the current settings.